Presynaptic inhibition and histamine in cerebral ganglion of Aplysia.
In the cerebral ganglion of Aplysia californica synaptic transmission between identified neurones undergoes a prolonged decrease of efficacy following activation of a separate afferent pathway. Synaptic efficacy was measured as the amplitude of a monosynaptic and unitary excitatory response (test excitatory postsynaptic potential = test EPSP) generated by intracellular presynaptic stimulation. Test EPSP depression occurs with a delay of about 20 s, and may have a total duration of several minutes. Test EPSP depression is associated with a hyperpolarization of the presynaptic neurone. It is concluded that the test EPSP depression is due to presynaptic inhibition. Histamine mimics the pre- and postsynaptic effects obtained with activation of secondary afferent pathways.
Hinzen
D H
DH
Riehl
J
J
D000818:Animals; D001048:Aplysia; D002490:Central Nervous System / Q000502:physiology; D005724:Ganglia / Q000378:metabolism / Q000502:physiology*; D006632:Histamine / Q000378:metabolism / Q000502:physiology*; D006633:Histamine Antagonists / Q000494:pharmacology; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects; D009433:Neural Inhibition / Q000187:drug effects; D018377:Neurotransmitter Agents / Q000494:pharmacology; D013569:Synapses
D006633:Histamine Antagonists; D018377:Neurotransmitter Agents; D006632:Histamine