Sunday, January 31, 2021

Listing of vitamins.

 Listing of vitamins.

     The list of vitamins and minerals below can give you an understanding of how particular different types of vitamins and minerals work in your body, how much of each nutrient you need every day, and what types of food to eat to ensure that you are getting an adequate supply. The recommendations in this vitamins chart are based largely on guidelines from the Institute of Medicine. Recommended amounts of different types of vitamins may be expressed in milligrams (mg), micrograms (mcg), or international units (IU), depending on the nutrient. Unless specified, values represent those for adults ages 19 and older.



VITAMIN
BENEFITS
RECOMMENDED AMOUNT (daily RDA* or daily AI**)
UPPER LIMIT (UL) per day
GOOD FOOD SOURCES
DID YOU KNOW?
RETINOIDS AND CAROTENE (vitamin A; includes retinol, retinal, retinyl esters, and retinoic acid and are also referred to as "preformed" vitamin A. Beta carotene can easily be converted to vitamin A as needed.)Essential for vision Lycopene may lower prostate cancer risk. Keeps tissues and skin healthy. Plays an important role in bone growth and in the immune system. Diets rich in the carotenoids alpha-carotene and lycopene seem to lower lung cancer risk. Carotenoids act as antioxidants. Foods rich in the carotenoids lutein and zeaxanthin may protect against cataractsM: 900 mcg (3,000 IU)W: 700 mcg (2,333 IU)Some supplements report vitamin A in international units (IU's).3,000 mcg (about 10,000 IU)Sources of retinoids: beef liver, eggs, shrimp, fish, fortified milk, butter, cheddar cheese, Swiss cheese

Sources of beta carotene: sweet potatoes, carrots, pumpkins, squash, spinach, mangoes, turnip greens
Many people get too much-preformed vitamin A from food and supplements. Large amounts of supplemental vitamin A (but not beta carotene) can be harmful to bones. Normal 0 false false false EN-US X-NONE X-NONE
THIAMIN (vitamin B1)Helps convert food into energy. Needed for healthy skin, hair, muscles, and brain and is critical for nerve function.M: 1.2 mg, W: 1.1 mgNot knownPork chops, brown rice, ham, soymilk, watermelons, acorn squashMost nutritious foods have some thiamin.
RIBOFLAVIN (vitamin B2)Helps convert food into energy. Needed for healthy skin, hair, blood, and brainM: 1.3 mg, W: 1.1 mgNot knownMilk, eggs, yoghurt, cheese, meats, green leafy vegetables, whole and enriched grains and cereals.Most Americans get enough of this nutrient.
NIACIN (vitamin B3, nicotinic acid)Helps convert food into energy. Essential for healthy skin, blood cells, brain, and nervous systemM: 16 mg, W: 14 mg35 mgMeat, poultry, fish, fortified and whole grains, mushrooms, potatoes, peanut butterNiacin occurs naturally in food and can also be made by your body from the amino acid tryptophan, with the help of B6.
PANTOTHENIC ACID (vitamin B5)Helps convert food into energy. Helps make lipids (fats), neurotransmitters, steroid hormones, and haemoglobinM: 5 mg, W: 5 mgNot knownWide variety of nutritious foods, including chicken, egg yolk, whole grains, broccoli, mushrooms, avocados, tomato productsDeficiency causes burning feet and other neurologic symptoms.
PYRIDOXINE (vitamin B6, pyridoxal, pyridoxine, pyridoxamine)Aids in lowering homocysteine levels and may reduce the risk of heart disease helps convert tryptophan to niacin and serotonin, a neurotransmitter that plays key roles in sleep, appetite, and moods. Helps make red blood cells Influences cognitive abilities and immune function31–50 years old: M: 1.3 mg, W: 1.3 mg; 51+ years old: M: 1.7 mg, W: 1.5 mg100 mgMeat, fish, poultry, legumes, tofu and other soy products, potatoes, noncitrus fruits such as bananas and watermelonsMany people don't get enough of this nutrient.
COBALAMIN (vitamin B12)Aids in lowering homocysteine levels and may lower the risk of heart disease. Assists in making new cells and breaking down some fatty acids and amino acids. Protects nerve cells and encourages their normal growth Helps make red blood cells and DNAM: 2.4 mcg, W: 2.4 mcgNot knownMeat, poultry, fish, milk, cheese, eggs, fortified cereals, fortified soymilkSome people, particularly older adults, are deficient in vitamin B12 because they have trouble absorbing this vitamin from food. Those on a vegan or vegetarian diet often don't get enough B12 as it's mostly found in animal products. They may need to take supplements. A lack of vitamin B12 can cause memory loss, dementia, and numbness in the arms and legs.
BIOTINHelps convert food into energy and synthesize glucose. Help make and break down some fatty acids. Needed for healthy bones and hairM: 30 mcg, W: 30 mcgNot knownMany foods, including whole grains, organ meats, egg yolks, soybeans, and fishSome are made by bacteria in the gastrointestinal tract. However, it's not clear how much of this the body absorbs.
ASCORBIC ACID (vitamin C)Foods rich in vitamin C may lower the risk for some cancers, including those of the mouth, oesophagus, stomach, and breast. Long-term use of supplemental vitamin C may protect against cataracts. Helps make collagen, a connective tissue that knits together wounds and supports blood vessel walls. Help make the neurotransmitters serotonin and norepinephrine Acts as an antioxidant, neutralizing unstable molecules that can damage cells. Bolsters the immune systemM: 90 mg, W: 75 mg Smokers: Add 35 mg2,000 mgFruits and fruit juices (especially citrus), potatoes, broccoli, bell peppers, spinach, strawberries, tomatoes, Brussels sproutsEvidence that vitamin C helps reduce colds has not been convincing.
CHOLINEHelps make and release the neurotransmitter acetylcholine, which aids in many nerve and brain activities. Plays a role in metabolizing and transporting fatsM: 550 mg, W: 425 mg3,500 mgMany foods, especially milk, eggs, liver, salmon, and peanutsNo, really the body makes small amounts of choline. But experts don't know whether this amount is enough at certain ages.
CALCIFEROL (vitamin D)Helps maintain normal blood levels of calcium and phosphorus, which strengthen bones. Helps form teeth and bones. Supplements can reduce the number of non-spinal fractures

31–70: 15 mcg (600 IU) 71+: 20 mcg (800 IU)

50 mcg (2,000 IU)Fortified milk or margarine, fortified cereals, fatty fishMany people don't get enough of this nutrient. While the body uses sunlight to make vitamin D, it cannot make enough if you live in northern climates or don't spend much time in the sun.

ALPHA-TOCOPHEROL (vitamin E)

Acts as antioxidant, neutralizing unstable molecules that can damage cells. Protects vitamin A and certain lipids from damage. Diets rich in vitamin E may help prevent Alzheimer's disease.M: 15 mg, W: 15 mg (15 mg equals about 22 IU from natural sources of vitamin E and 33 IU from synthetic vitamin E)1,000 mg (nearly 1,500 IU natural vitamin E; 2,200 IU synthetic)Wide variety of foods, including vegetable oils, salad dressings and margarine made with vegetable oils, wheat germ, leafy green vegetables, whole grains, nutsVitamin E does not prevent wrinkles or slow other ageing processes.
FOLIC ACID (vitamin B9, folate, folacin)Vital for new cell creation helps prevent brain and spine birth defects when taken early in pregnancy; should be taken regularly by all women of child-bearing age since women may not know they are pregnant in the first weeks of pregnancy. Can lower levels of homocysteine and may reduce heart disease risk May reduce the risk for colon cancer. Offsets breast cancer risk among women who consume alcoholM: 400 mcg, W: 400 mcg1,000 mcgFortified grains and cereals, asparagus, okra, spinach, turnip greens, broccoli, legumes like black-eyed peas and chickpeas, orange juice, tomato juiceMany people don't get enough of this nutrient. Occasionally, folic acid masks a B12 deficiency, which can lead to severe neurological complications. That's not a reason to avoid folic acid; just be sure to get enough B12.
PHYLLOQUINONE, MENADIONE (vitamin K)Activates proteins and calcium essential to blood clotting. May help prevent hip fracturesM: 120 mcg, W: 90 mcgNot knownCabbage, liver, eggs, milk, spinach, broccoli, sprouts, kale, collards, and other green vegetablesIntestinal bacteria make a form of vitamin K that accounts for half your requirements. If you take an anticoagulant, keep your vitamin K intake consistent.
MINERAL
BENEFITS
RECOMMENDED AMOUNT (daily RDA* or daily AI**)
UPPER LIMIT (UL) per day
GOOD FOOD SOURCES
DID YOU KNOW?
CALCIUMBuilds and protects bones and teeth. Helps with muscle contractions and relaxation, blood clotting, and nerve impulse transmission. Plays a role in hormone secretion and enzyme activation. Helps maintain healthy blood pressure31–50: M: 1,000 mg, W: 1,000 mg 51-70: M: 1,000 mg, W: 1,200 mg, 71+: M: 1,200 mg, W: 1,200 mg2,500 mgYoghurt, cheese, milk, tofu, sardines, salmon, fortified juices, leafy green vegetables, such as broccoli and kale (but not spinach or Swiss chard, which have binders that lessen absorption)Adults absorb roughly 30% of calcium ingested, but this can vary depending on the source. Diets very high in calcium may increase the risk of prostate cancer.
CHLORIDEBalances fluids in the body. A component of stomach acid, essential to digestion14-50: M/W: 2.3 g, 51-70 M/W: 2.0 g, 71+: M/W: 1.8 gNot knownSalt (sodium chloride), soy sauce, processed foodsNew recommendations (DRIs) for chloride are under development by the Institute of Medicine.
CHROMIUMEnhances the activity of insulin, helps maintain normal blood glucose levels, and is needed to free energy from glucose14–50: M: 35 mcg, 14-18: W: 24 mcg 19-50: W: 25 mcg 51+: M: 30 mcg, W: 20 mcgNot knownMeat, poultry, fish, eggs, potatoes, some cereals, nuts, cheeseUnrefined foods such as brewer's yeast, nuts, and cheeses are the best sources of chromium, but brewer's yeast can sometimes cause bloating and nausea, so you may choose to get chromium from other food sources.
COPPERPlays an important role in iron metabolism and the immune system. Helps make red blood cellsM: 900 mcg, W: 900 mcg10,000 mcgLiver, shellfish, nuts, seeds, whole-grain products, beans, prunes, cocoa, black pepperMore than half of the copper in foods is absorbed.
FLUORIDEEncourages strong bone formation. Keeps dental cavities from starting or worseningM: 4 mg, W: 3 mg10 mgWater that is fluoridated, toothpaste with fluoride, marine fish, teasHarmful to children in excessive amounts.
IODINEPart of the thyroid hormone, which helps set body temperature and influences nerve and muscle function, reproduction, and growth. Prevents goitre and a congenital thyroid disorderM: 150 mcg, W: 150 mcg1,100 mcgIodized salt, processed foods, seafoodTo prevent iodine deficiencies, some countries add iodine to salt, bread, or drinking water.
IRONHelps haemoglobin in red blood cells and myoglobin in muscle cells ferry oxygen throughout the body. Needed for chemical reactions in the body and for making amino acids, collagen, neurotransmitters, and hormones19–50: M: 8 mg, W: 18 mg 51+: M: 8 mg, W: 8 mg45 mgRed meat, poultry, eggs, fruits, green vegetables, fortified bread and grain productsMany women of childbearing age don't get enough iron. Women who do not menstruate probably need the same amount of iron as men. Because iron is harder to absorb from plants, experts suggest vegetarians get twice the recommended amount (assuming the source is food).
MAGNESIUMNeeded for many chemical reactions in the body Works with calcium in muscle contraction, blood clotting, and regulation of blood pressure. Helps build bones and teeth18+: M: 420 mg, W: 320 mg350 mg (Note: This upper limit applies to supplements and medicines, such as laxatives, not to dietary magnesium.)Green vegetables such as spinach and broccoli, legumes, cashews, sunflower seeds and other seeds, halibut, whole-wheat bread, milkThe majority of magnesium in the body is found in bones. If your blood levels are low, your body may tap into these reserves to correct the problem.
MANGANESEHelps form bones. Helps metabolize amino acids, cholesterol, and carbohydratesM: 2.3 mg, W: 1.8 mg11 mgFish, nuts, legumes, whole grains, teaIf you take supplements or have manganese in your drinking water, be careful not to exceed the upper limit. Those with liver damage or whose diets supply abundant manganese should be especially vigilant.
MOLYBDENUMPart of several enzymes, one of which helps ward off a form of severe neurological damage in infants that can lead to early deathM: 45 mcg, W: 45 mcg2,000 mcgLegumes, nuts, grain products, milkMolybdenum deficiencies are rare.
PHOSPHORUSHelps build and protect bones and teeth. Part of DNA and RNA. Helps convert food into energy. Part of phospholipids, which carry lipids in blood and help shuttle nutrients into and out of cellsM: 700 mg, W: 700 mg31–70: 4,000 mg 71+: 3,000 mgWide variety of foods, including milk and dairy products, meat, fish, poultry, eggs, liver, green peas, broccoli, potatoes, almondsCertain drugs bind with phosphorus, making it unavailable and causing bone loss, weakness, and pain.
POTASSIUMBalances fluids in the body. Helps maintain a steady heartbeat and send nerve impulses. Needed for muscle contractions. A diet rich in potassium seems to lower blood pressure. Getting enough potassium from your diet may benefit bonesM: 4.7 g, W: 4.7 gNot knownMeat, milk, fruits, vegetables, grains, legumesFood sources do not cause toxicity, but high-dose supplements might.
SELENIUMActs as an antioxidant, neutralizing unstable molecule that can damage cells. Helps regulate thyroid hormone activityM: 55 mcg, W: 55 mcg400 mcgOrgan meats, seafood, walnuts, sometimes plants (depends on soil content), grain productsResearchers are investigating whether selenium may help reduce the risk of developing cancer, but with mixed results.
SODIUMBalances fluids in the body. Help send nerve impulses. Needed for muscle contractions. Impacts blood pressure; even modest reductions in salt consumption can lower blood pressureM: 2,300 mg, W: 2,300 mgNot determinedSalt, soy sauce, processed foods, vegetablesWhile experts recommend that people limit sodium intake to 2,300 mg, most Americans consume 4,000–6,000 mg a day.
SULFURHelps form bridges that shape and stabilize some protein structures. Needed for healthy hair, skin, and nailsUnknownUnknownProtein-rich foods, such as meats, fish, poultry, nuts, legumesSulfur is a component of thiamin and certain amino acids. There is no recommended amount for sulfur. Deficiencies occur only with a severe lack of protein.
ZINCHelps form many enzymes and proteins and create new cells. Frees vitamin A from storage in the liver. Needed for immune system, taste, smell, and wound healing. When taken with certain antioxidants, zinc may delay the progression of age-related macular degenerationM: 11 mg, W: 8 mg40 mgRed meat, poultry, oysters and some other seafood, fortified cereals, beans, nutsBecause vegetarians absorb less zinc, experts suggest that they get twice the recommended requirement of zinc from plant foods.
*Recommended dietary allowance **Adequate intake

How to boost your immune system?

 How to boost your immune system?

     There appears to be a connection between nutrition and immunity in the elderly. A form of malnutrition that is surprisingly common even in affluent countries is known as "micronutrient malnutrition." Micronutrient malnutrition, in which a person is deficient in some essential vitamins and trace minerals that are obtained from or supplemented by diet, can happen in the elderly. Older people tend to eat less and often have less variety in their diets. One important question is whether dietary supplements may help older people maintain a healthier immune system. Older people should discuss this question with their doctor.

Diet and your immune system

       Like any fighting force, the immune system army marches on its stomach. Healthy immune system warriors need good, regular nourishment. Scientists have long recognized that people who live in poverty and are malnourished are more vulnerable to infectious diseases. Whether the increased rate of disease is caused by malnutrition's effect on the immune system, however, is not certain. There are still relatively few studies on the effects of nutrition on the immune system of humans.

There is some evidence that various micronutrient deficiencies — for example, deficiencies of zinc, selenium, iron, copper, folic acid, and vitamins A, B6, C, and E — alter immune responses in animals, as measured in the test tube. However, the impact of these immune system changes on the health of animals is less clear, and the effect of similar deficiencies on the human immune response has yet to be assessed. 

                           


Improve immunity with herbs and supplements

          Walk into a store, and you will find bottles of pills and herbal preparations that claim to "support immunity" or otherwise boost the health of your immune system. Although some preparations have been found to alter some components of immune function, thus far there is no evidence that they actually bolster immunity to the point where you are better protected against infection and disease. Demonstrating whether a herb — or any substance, for that matter — can enhance immunity is, as yet, a highly complicated matter. Scientists don't know, for example, whether a herb that seems to raise the levels of antibodies in the blood is actually doing anything beneficial for overall immunity.


Exercise: Good or bad for immunity?

          Regular exercise is one of the pillars of healthy living. It improves cardiovascular health, lowers blood pressure, helps control body weight, and protects against a variety of diseases. But does it help to boost your immune system naturally and keep it healthy? Just like a healthy diet, exercise can contribute to general good health and therefore to a healthy immune system. It may contribute even more directly by promoting good circulation, which allows the cells and substances of the immune system to move through the body freely and do their job efficiently.


Tuesday, November 17, 2020

BRS Biochemistry, Molecular Biology, and Genetics

 BRS Biochemistry, Molecular Biology, and Genetics


BRS Biochemistry, Molecular Biology, and Genetics PDF 7th Edition is a superb assist for USMLE Step 1 preparation and for coursework in biochemistry, molecular biology, and genetics. Totally up to date for its sixth version, chapters are written in an overview format and embody pedagogical options reminiscent of bolded key phrases, figures, tables, algorithms, and highlighted medical correlates. USMLE-style questions and solutions observe every chapter and a complete examination seems on the finish of the guide. 

Overview

Practical, approachable, and perfect for today’s busy medical students and practitioners, BRS Biochemistry, Molecular Biology, and Genetics, Seventh Edition helps ensure excellence in-class exams and on the USMLE Step 1. The popular Board Review Series outline format keeps content succinct and accessible for the most efficient review, accompanied by bolded key terms, detailed figures, quick-reference tables, and other aids that highlight important concepts and reinforce understanding. This revised edition is updated to reflect the latest perspectives in biochemistry, molecular biology, and genetics, with a clinical emphasis essential to success in practice. New Clinical Correlation boxes detail the real-world application of chapter concepts and updated USMLE-style questions with answers test retention and enhance preparation for board exams and beyond.


                                      DOWNLOAD PDF


Sunday, November 8, 2020

Goljan Rapid Review Pathology PDF FREE Download [Direct Links]

 

Goljan Rapid Review Pathology PDF FREE Download [Direct Links]

In this post, we have shared an overview and download link of Goljan Rapid Review Pathology PDF. Read the overview below and download using links given at the end of the post.

Edward F. Goljan’s Rapid Review Pathology is truly a masterpiece because of its highly sophisticated content structure which has been devised in such a logical manner that it makes studying pathology (often considered a terrifying subject) easy and rewarding.

This book is very useful for medical students especially those who are preparing for the USMLE Step 1 exam. It serves as a perfect complement to the First Aid for Step 1. Goljan Pathology is also known among the medical students as the “Robbins-Pathoma Baby” because it offers a very comprehensive and detailed text like the Robbins Pathology and high-yield presentation of important facts, as seen in the Pathoma 2017. If you are looking for one good book for review of pathology then consider using this book and we are sure that you will never regret making this decision.




Download Lectures





Table of Contents

Below is the complete table of the content presented in the  Goljan Rapid Review Pathology 4th Edition PDF:

  1. Diagnostic testing
  2. Cell injury
  3. Inflammation and repair
  4. Immunopathology
  5. Water, electrolyte, acid-base, and hemodynamic disorders
  6. Genetic and developmental disorders
  7. Environmental pathology
  8. Nutritional disorders
  9. Neoplasia
  10. Vascular disorders
  11. Heart disorders
  12. Red blood cell disorders
  13. White blood cell disorders
  14. Lymphoid tissue disorders
  15. Hemostasis disorders
  16. Immunohematology disorders
  17. Upper and lower respiratory disorders
  18. Gastrointestinal disorders
  19. Hepatobiliary and pancreatic disorders
  20. Kidney disorders
  21. Lower urinary tract and male reproductive disorders
  22. Female reproductive disorders and breast disorders
  23. Endocrine disorders
  24. Musculoskeletal and soft tissue disorders
  25. Skin disorders
  26. Nervous system and special sensory disorders.

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Fundamentals of Pathology Pathoma 2020 PDF FREE Download [Direct Link]

 Fundamentals of Pathology Pathoma 2020 PDF FREE Download [Direct Link]

 Fundamentals of Pathology aims at providing general principles of pathology and its associated disciplines and is not intended as a working guide to patient care, drug administration or treatment. Medicine is a constantly evolving field and changes in practice regularly occur. It is the responsibility of the treating practitioner, relying on independent expertise and knowledge of the patient, to determine the best treatment and method of application.


Author:

The author of this book Husain A. Sattar, MD recommends using Fundamentals of Pathology Pathoma 2018 PDF alongside the Pathoma video lectures. As the preface of the book indicates, the publishers have provided ample space for note-taking/writing so that when exam time comes around, these notes would turn out to be very beneficial to the readers.





Contents:

CHAPTER 1: Growth adaptations, cellular injury, and cell death

CHAPTER 2: Inflammation, inflammatory disorders, and wound healing

CHAPTER 3: Principles of Neoplasia

CHAPTER 4: Hemostasis and related disorders

CHAPTER 5: Red blood cell disorders

CHAPTER 6: White blood cell disorders

CHAPTER 7: Vascular Pathology

CHAPTER 8: Cardiac Pathology

CHAPTER 9: Respiratory Tract Pathology

CHAPTER 10: Gastrointestinal Pathology

CHAPTER 11: Exocrine pancreas, gallbladder, and liver pathology

CHAPTER 12: Kidney and urinary tract pathology

CHAPTER 13: Female genital system and gestational pathology

CHAPTER 14: Male genital system pathology

CHAPTER 15: Endocrine Pathology

CHAPTER 16: Breast Pathology

CHAPTER 17: Central Nervous System Pathology

CHAPTER 18: Musculoskeletal Pathology

CHAPTER 19: Skin Pathology

Videos:

The best way to use this book, according to Husain A. Sattar, MD, is to read the book first, then do the Pathoma video lectures and then reread the material. This method would help students building very firm concepts and reinforce whatever is learned.

                             Download Videos



                                                                                                                                                                                          Download pdf 2020


                    





Sunday, November 1, 2020

Cholinergic Antagonist

Cholinergic Antagonist:

These bind to cholinergic receptors and block them. They are also called parasympatholytics, cholinergic blockers or anticholinergic drugs'



Classification:



ATROPINE:

It is a tertiary amine extracted from belladonna alkaloid. It has a high affinity for muscarinic receptors binds competitively to prevent acetylcholine from binding. Half-life is 4 hours.




ACTIONS:

EYE:

Atropine causes dilation of pupil called mydriasis, unresponsiveness to light and cycloplegia. It increases intraocular pressure.

GIT:

It is antispasmodic to reduce the activity of the GIT. It reduces secretions and relieves intestinal and biliary colics.

CNS:

It causes excitement, hallucinations and delirium.

URINARY SYSTEM;

It decreases the tone of the smooth muscle of the bladder and causes urinary retention.

CVS:

It has a divergent effect on the heart. At a low dose, it decreases heart rate. At a high dose, it increases heart rate.

SECRETIONS:

It blocks the salivary glands causing xerostomia. It also decreases sweat and lacrimal glandular secretion.

Therapeutic uses:

Ophthalmic:

It causes both mydriatic and cycloplegic effects. It is used in the measurement of refractive errors.

Antispasmodic
Bradycardia
Anti secretory
Anti dote for cholinergic agonist

Adverse effects:

Dry mouth
Blurred vision
Tachycardia
Urinary retention
Constipation
Restlessness
Confusion
Hallucinations

Signs of atropine toxicity:

Hot as a hare ( hyperthermia)
Dry as bone( dry skin)
Red as a beat(flushed)
Blind as a bat(mydriasis)
Mad as a hatter(delirium)

The antidote of atropine:

Physostigmine

                      



                                     Scopolamine

It is also a tertiary amine produces similar effects to those of atropine but has greater effects on CNS.

Clinical uses:

Scopolamine is used to prevent motion sickness, postoperative nausea and vomiting.












Saturday, October 31, 2020

The cholinergic Agonist

 The cholinergic Agonist:

    The preganglionic fibers terminating in the adrenal medulla, the autonomic ganglia both parasympathetic and sympathetic and the postganglionic fibers of the parasympathetic use ACETYLCHOLINE as a neurotransmitter. In addition, ACETYLCHOLINE innervates the muscle of the somatic system and also play important role in the CNS.

                                   


Neurotransmission at Cholinergic Neuron:

1.Synthesis of ACETYLCHOLINE:

      Choline is transported from the extracellular fluid into the cytoplasm of the cholinergic neuron by energy-dependent carrier system that cotransports sodium and is inhibited by the drug HEMICHOLINIUM. Choline has quaternary nitrogen and a permanent positive charge thus cannot diffuse through the membrane. Choline acetyltransferase catalyzes the reaction of the choline with acetyl coenzyme A to form acetylcholine an ester in the cytosol. The ACh is then stored in the storage vesicles. The released ACh interacts with cholinergic receptors on effector cells and activates them. In the synaptic cleft, the ACh is rapidly hydrolysed by Acetylcholinesterase AChE enzyme.

                             

CHOLINESTRASE:

It is an enzyme and has two types:

1.True cholinesterase:

It is found in cholinergic neurons, ganglia, RBCs and neuromuscular junction. It rapidly hydrolysis ACh and methacholine into choline and acetate in the synaptic cleft.

2.Pseudocholinesterase or Butyrylcholine:

It is found in plasma, liver and glial cells. It can hydrolyse ACh but does not hydrolyse methacholine. Hydrolysis is slow.

2.Cholinergic receptors:

These are of two types:

1.MUSCARINIC RECEPTORS               2.NICOTINIC RECEPTORS

MUSCARINIC RECEPTORS:

There are five subclasses. M1 found in gastric glands, autonomic ganglia and CNS. M2 is found in the heart. M3 is present in smooth muscles, exocrine glands and epithelial cells. M4 & M5 are present in CNS.
M1 & M3 are Gq coupled while M2 is Gi-coupled.
 
                                       


NICOTINIC RECEPTORS:

These are of 2 subtypes:

Those present at the neuromuscular junction are called Nm and all others are called Nn. These are ionotropic receptors they activate sodium channels and cause depolarization of the cholinergic neuron.

Directly acting Cholinergic Agonist:

1.Choline esters                                                 2.Alkaloids

Acetylcholine                                                      Pilocarpine
Bethanechol                                                         Muscarine
Carbachol

Acetylcholine:

It is quaternary ammonium so it can not penetrate membranes. It is the neurotransmitter at parasympathetic and somatic as well as autonomic ganglia. It is rapidly metabolized by cholinesterase. ACh has both muscarinic and nicotinic activity.

Actions of ACh:

HEART:  

 It mimics the effects of vagal stimulation. It decreases heart rate and cardiac output.

Blood pressure:

Injection of ACh causes vasodilation and lower blood pressure.

Other actions:

In the gastrointestinal tract, it increases salivary secretion, increases gastric acid and stimulates intestinal secretions and mobility. It also enhances bronchial secretion and causes bronchoconstriction.
It causes constriction of ciliary muscles of an eye for near vision and constriction of sphincter pupillae muscle, causing miosis.

Bethanechol:

It is not hydrolysed by AChE and is inactivated bt other esterases. It lacks nicotinic actions but does have strong muscarinic activity.

Therapeutic uses;

It is used to stimulate the atonic bladder, neurogenic atony as well as megacolon.

Adverse effects:

sweating, salivation, flushing, decreased blood pressure, nausea, abdominal pain. diarrhoea and bronchospasm. Atropine sulfate is used to overcome its side effects.

Carbachol:

It has both muscarinic and nicotinic actions, a poor substrate of AChE. It is used to provide miosis for eye surgery. It may first stimulate and then depress these systems.

Pilocarpine:

It is a tertiary amine and is stable to hydrolysis by AChE. It can penetrate CNS and has muscarinic activity.

Therapeutic uses:

It is a drug of choice for the emergency lowering of intraocular pressure for both open and closed-angle glaucoma. It is also used in xerostomia and Sjogren syndrome.

Adverse effects:

blurred vision, night blindness, profuse sweating and salivation. Atropine is used to counteract the toxicity of pilocarpine.

5% Minoxidil Spray for Hair Loss: A Complete Clinical Guide

 Table of Contents 1. Introduction 2. Mechanism of Action 3. Pharmacokinetics and Pharmacodynamics 4. Indications 5. Contraindications 6. Dr...