benzodiazepines catecholamines congresses drug drugeffects electroreceptors gaba gamma-aminobutyricacid mechanoreceptors neuraltransmission neurochemistry neurons neuropharmacology neurotransmitteragents neurotransmitters physiology qv38g1031980 receptors sensoryreceptorcells synapses synaptictransmission thermoreceptors wl102t828c1976 wl104a512p1975