pharmacology

Mechanisms of action & Classification  Adrenergic drugs are medications that stimulate or inhibit adrenergic receptors. Adrenergic receptors mediate the action of noradrenaline, also known as norepinephrine; and adrenaline, also known as epinephrine. Adrenergic neurotransmission is responsible for the body’s sympathetic response - the “fight or flight” state - which dilates pupils, increases heart rate and respiratory rate, diverts blood flow to the muscles, inhibits activities that are not essential in emergency, and releases stored energy. Adrenergic receptors are also active in the central nervous system, in processes such as memory and alertness. There are several types of adrenergic receptors,all of which are G-protein coupled, but they differ in several aspects:- They couple with different G-proteins, leading to different downstream signalings, and hence different cellular responses. - They differ in sensitivity to different drugs. - While several receptors may coexist i...

How Vaccines work ?                                                                               Vaccines prepare the immune system, getting it ready to fight disease-causing organisms, called pathogens. To understand how vaccines work, we must first learn how our immune system responds to invading pathogens. When a new pathogen enters the body, it meets with the body’s first-line defense, the innate division of the immune system. The innate response is immediate, but non-specific,meaning it destroys all foreign invaders without discrimination. Fever is one of the signs that the body is fighting the disease at this stage. If this fails to contain the infection, the adaptive immune system comes into play. The adaptive response is more effective, but it may take many days to activate, during...

                                                   An Overview : Diuretics    Diuretics are substances that increase production of urine. Most diuretics act to increase excretion of sodium, which is followed by water. Because increased urine production   results in reduced blood volume, diuretics arommonly used to treat primary hypertension and edema. Changes in body fluid and electrolytes induced by diuretics can also  be therapeutic for some other conditions. Sodium and water  are filtered in the glomerular capsule of nephrons, then reabsorbed back to the blood at various sites along the renal tubule. Different classes of diuretics prevent sodium  re -absorption, and thus increase sodium loss, at different sites, by different mechanisms. Carbonic anhydrase inhibitors inhibit the enzyme carbonic anhydras...

  What is Diabetes ?  Diabetes refers to a group of conditions characterized by a high level of blood glucose, commonly referred to as blood sugar. Too much sugar in the blood can cause serious, sometimes life-threatening health problems.There are two types of chronic diabetic conditions: type 1 diabetes and type 2 diabetes. Pregnant women may acquire a transient form of the disease called “gestational diabetes”which usually resolves after the birth of baby. Pre-diabetes is when the blood sugar level is at the borderline: higher than normal, but lower than in diabetics. Prediabetes mayor may not progress to diabetes. During food digestion, carbohydrates - or carb - break down into glucose which is carried by the bloodstream to various organs of the body. Insulin is a hormone produced by beta cells of the pancreas and is necessary for glucose intake by target cells. In healthy people, beta cells of the pancreas produce insulin; insulin binds to its receptor on target cells and ...

 HISTAMINNE Histamine, meaning 'tissue amine' (histos-tis- sue) is almost ubiquitously present in animal tissues and in certain plants, e.g. stinging nettle. Its pharmacology was studied in detail by Dale in the beginning of the 20th century when close  parallelism was noted between its actions and the  manifestations of certain allergic reactions. Histamine  was implicated as a mediator of hypersensitivity  phenomena and tissue injury reactions. It is now  known to play important physiological roles. Histamine is present mostly within storage  granules of mast cells. Tissues rich in histamine  are skin, gastric and intestinal mucosa, lungs,  liver and placenta. Nonmast cell histamine  Occurs in brain, epidermis, gastric mucosa  and growing regions. Turnover of mast cell  histamine is slow, while that of nonmast cell  histamine is fast. Histamine is also present  in blood, most body secretions, venoms and  pathol...

THYROID HORMONES The thyroid gland secretes 3 3 hormones-thyro-xine (T4), triiodothyronine (T,) and calcitonin. The former two are produced by thyroid follicles,have similar biological activity and the term 'thyroid hormone' is restricted to these only. Calcitonin produced by interfollicular "C cells is chemically and biologically entirely different. It is considered along with parathormone with which it regulates calcium metabolism.           The physiological significance of thyroid gland was recognized only after Graves and Basedow (1835, 1840) associated the clinical features of the Graves' disease' with swelling of thyroid gland and Gull (1874) correlated myxoedema with its atrophy. Kendall (1915) obtained erystalline thyroxine and postulated its chemical formula which was confirmed in 1926. Thyroxine was the first hormone to be synthesized in the laboratory. Since T could not account for all the biological activity of thy- roid extract, search was made and...

    NSAIDs and prostaglandin (PG)    synthesis inhibition     In 1971 Vane and coworkers made the landmark observation that aspirin and some NSAIDs blocked prostaglandin (PG) generation. This is now  considered to be the major mechanism of action of NSAIDs. Prostaglandins, prostacyclin (PG I,) and thromboxane A, (TXA,) are produced from arachidonic acid by the enzyme cyclooxygenase (see p. 198) which exists in a constitutive (COX-1) and an inducible (COX-2) isoforms; the former serves physiological "house keeping functions, while the latter, normally present in minute quantities, is induced by cytokines and other signal molecules at the site of inflammation. This leads to generation of PGs locally which mediate many of the inflammatory changes. However, COX-2 is constitutively present at some sites in brain, in juxtaglomerular cells and in the foetus; it may serve physiological role at these sites. Most NSAIDs inhibit COX-1 and COX-2 nonselectively, bu...

General Anaesthetics General anesthetics (GAs) are drugs which produce reversible loss of all sensation and consciousness.The cardinal features of general anaesthetic:   Loss of all sensation,specially pain Sleep (unconsciousness) and amnesia Immobility and muscle relaxation Abolition of somatic and autonomic reflexes In the modern practice of balanced anaesthetics,this modalities are achieved by using combination of inhaled and i.v. drugs,each for a specific purpose. Anaesthetics has developed as a highly specialized science in itself.