Acetylcholine (ACh) is too rapidly hydrolyzed and inactivated by acetylcholinesterase (AChE) to be of any therapeutic use; however, its action can be mimicked by other substances, namely direct or indirect parasympathomimetics (cholinomimetics).
Substances acting antagonistically at the M-cholinoceptor are designated parasympatholytics (prototype: the alkaloid atropine; actions shown in red in the panels). Therapeutic use of these agents is complicated by their low organ selectivity.
Antiadrenergics are drugs capable of lowering transmitter output from sympathetic neurons, i.e., “sympathetic tone”. Their action is hypotensive (indication: hypertension) however, being poorly tolerated, they enjoy only limited therapeutic use.
Beta-Sympatholytics (Beta Blockers) are antagonists of norepiphephrine and epinephrine at β- adrenoceptors; they lack affinity for alpha-receptors. Beta-Blockers protect the heart from the oxygen wasting effect of sympathetic inotropism by blocking cardiac beta-receptors; thus, cardiac work can no longer be augmented above basal levels (the heart is “coasting”). This effect is utilized prophylactically in angina pectoris to prevent myocardial stress that could trigger an ischemic attack.
Infections due to fungi are usually confined to the skin or mucous membranes: local or superficial mycosis. However, in immune deficiency states, internal organs may also be affected: systemic or deep mycosis. Mycoses are most commonly due to dermatophytes, which affect the skin, hair, and nails following external infection.
The therapeutic principle applicable to both Tuberculosis and Leprosy is combined treatment with two or more drugs. Combination therapy prevents the emergence of resistant Mycobacteria and Mycobacterial Infections.
Benzodiazepines modify affective responses to sensory perceptions; specifically, they render a subject indifferent towards anxiogenic stimuli, i.e., anxiolytic action. Furthermore, benzodiazepines exert sedating, anticonvulsant, and muscle-relaxant (myotonolytic) effects.
Epilepsy is a chronic brain disease of diverse etiology; it is characterized by recurrent paroxysmal episodes of uncontrolled excitation of brain neurons. Involving larger or smaller parts of the brain,…
Parkinson’s disease (shaking palsy) and its syndromal forms are caused by a degeneration of nigrostriatal dopamine neurons. Pharmacotherapeutic measures are aimed at restoring dopaminergic function or suppressing cholinergic hyperactivity.
Many bacteria (e.g., Vibrio cholerae) secrete toxins that inhibit the ability of mucosal enterocytes to absorb NaCl and water and, at the same time, stimulate mucosal secretory activity. Bacteria or…