Modulation of mechanosensory threshold in Aplysia by serotonin, small cardioactive peptideB (SCPB), FMRFamide, acetylcholine, and dopamine.
Mechanosensory threshold of tail sensory neurons in Aplysia was tested after injecting the tail with neuromodulators known to affect defensive behavior in this animal. Serotonin (5-HT) and small cardioactive peptide (SCPB) reduced peripheral threshold, while FMRFamide, acetylcholine (ACh), and dopamine increased threshold. FMRFamide and ACh also reduced spontaneous activity of sensory neurons. Glutamate and taurine had no effect. SCPB effects persisted for 15-30 min after washout. Functional similarities between peripheral and central effects of these neuromodulators support the hypothesis of coordinate modulation of both regions of the sensory neuron by the same set of modulators following noxious stimulation.
Billy
A J
AJ
Department of Physiology and Cell Biology, University of Texas Medical School, Houston 77225.
Walters
E T
ET
D000109:Acetylcholine / Q000494:pharmacology*; D000818:Animals; D001048:Aplysia / Q000502:physiology*; D004298:Dopamine / Q000494:pharmacology*; D019835:FMRFamide; D066298:In Vitro Techniques; D008465:Mechanoreceptors / Q000187:drug effects*; D009475:Neurons, Afferent / Q000502:physiology; D009479:Neuropeptides / Q000494:pharmacology*; D018377:Neurotransmitter Agents / Q000494:pharmacology*; D012684:Sensory Thresholds / Q000187:drug effects*
D009479:Neuropeptides; D018377:Neurotransmitter Agents; D019835:FMRFamide; C041307:small cardioactive peptide B; D000109:Acetylcholine; D004298:Dopamine