Central nervous system agents anxiolytics

CNS agents of the 1,4 benzodiazepine class presumably exert their effects by binding at stereo specific receptors at several sites within the central nervous system (CNS). Alprazolam like other benzodiazepines exerts its anxiolytic action by potentiating GABA activity. GABA is a neurotransmitter which inhibits the CNS activity. Alprazolam acts preferentially in midbrain, ascending reticular formation (which maintains wakefulness) and on limbic system (thought and mental functions). 

Little is known about the nervous systems of cestodes and trematodes except that they probably differ from those of nematodes, since milbemycins and avermectins have no effect on them. However, a highly effective anti schistosomal and antitapeworm agent, praziquantel (see Chapter 54 Clinical Pharmacology of the Anthelmintic Drugs), is known to enhance Ca2+ influx and induce muscular contraction in those parasites, though it exerts no action on nematodes or insects. Some benzodiazepine derivatives have activities similar to those of praziquantel these activities are unrelated to the anxiolytic activities in the mammalian central nervous system. The nerves and muscles in schistosomes and tapeworms are thus interesting subjects for future chemotherapeutic studies. 

As to be expected from a peptide that has been highly conserved during evolution, NPY has many effects, e.g. in the central and peripheral nervous system, in the cardiovascular, metabolic and reproductive system. Central effects include a potent stimulation of food intake and appetite control [2], anxiolytic effects, anti-seizure activity and various forms of neuroendocrine modulation. In the central and peripheral nervous system NPY receptors (mostly Y2 subtype) mediate prejunctional inhibition of neurotransmitter release. In the periphery NPY is a potent direct vasoconstrictor, and it potentiates vasoconstriction by other agents (mostly via Yi receptors) despite reductions of renal blood flow, NPY enhances diuresis and natriuresis. NPY can inhibit pancreatic insulin release and inhibit lipolysis in adipocytes. It also can regulate gut motility and gastrointestinal and renal epithelial secretion. 

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