Canadian journal of physiology and pharmacology
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Can. J. Physiol. Pharmacol. · Dec 1978
Picrotoxin prevents habituation of the gill withdrawal reflex in Aplysia.
The gill withdrawal reflex evoked by tactile stimulation of the siphon in Aplysia habituates with repeated presentation of the stimulus. This adaptive behaviour is mediated by the integrated activity of the central (CNS) and peripheral (PNS) nervous systems. The PNS mediates the basic reflex and its habituation while the CNS exerts both suppressive and facilitatory control over the PNS. ⋯ Thus the reflex amplitude was increased, the reflex latency decreased, and repeated stimulation did not result in habituation. This effect of picrotoxin was completely reversible. It is thus proposed that gamma-aminobutyric acid, a putative neurotransmitter, plays an important role in the mediation of the CNS's suppressive influence.