Cognition enhancing agents

Cognition enhancing agents, 39, 59 Coronary vasodilators, 118 Cromitrile, 137... 

Be able to understand the unique psychopharmacological mechanisms of action of the major antidepressants, anxiolytics, antipsychotics, cognitive enhancing agents, and drugs of abuse. 

DuP 753 is an orally active AT receptor antagonist and as of this writing is in clinical trials as an antihypertensive (see Cardiovascularagents). AT-11 antagonists affect the brain RAS system to enhance ACh release offering the possibiUty that these agents may function as cognition enhancers. 

In this chapter, we use the term cognitive enhancers to refer to two classes of pharmacological agents used in the treatment of Alzheimer s disease the cholinesterase inhibitors and the A-methyl-D-aspartate (NMDA) receptor antagonists. 

It improves the functioning of the brain involved in cognitive processes e.g. memory, thought, learning in normal and in subnormal conditions. It is categorized as nootropic agent (cognition enhancers). 

Neurotransmitters are removed by translocation into vesicles or destroyed in enzyme-catalysed reactions. Acetylcholine must be removed from the synaptic cleft to permit repolarization and relaxation. A high affinity acetylcholinesterase (AChE) (the true or specific AChE) catalyses the hydrolysis of acetylcholine to acetate and choline. A plasma AChE (pseudo-AChE or non-specific AChE) also hydrolyses acetylcholine. A variety of plant-derived substances inhibit AChE and there is considerable interest in AChE inhibitors as potential therapies for cognition enhancement and for Alzheimer s disease. Organophosphorous compounds alkylate an active site serine on AChE and the AChE inhibition by this mechanism is the basis for the use of such compounds as insecticides (and unfortunately also as chemical warfare agents). Other synthetics with insecticidal and medical applications carbamoylate and thus inactivate AChE (Table 6.4). 

Some of these agents appear to have a very selective action at Hs-receptors, though there is some cross-talk with 5-HT3 receptors. None of these agents are used therapeutically yet, but suggested applications include inhibition of neurogenic microvascular leakage in airways, prevention of myocardial ischaemia, as anticonvulsants, appetite suppressants and cognition enhancers. 

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