Neuromodulation by 5-hydroxytryptamine in the antennal lobe of the sphinx moth Manduca sexta.
Using intracellular recording techniques, we have begun to examine the effects of 5-hydroxytryptamine (5-HT) on antennal-lobe (AL) neurones in the brain of the adult moth Manduca sexta. 5-HT modulated the responses of local interneurones and projection neurones, which were recognized on the basis of well-established electrophysiological criteria, to primary synaptic input elicited by electrical stimulation of the ipsilateral antennal nerve. 5-HT applied at low concentration (10(-8) mol l-1) reduced the excitatory responses evoked by electrical stimulation of the antennal nerve, whereas at high concentration (10(-4) mol l-1), 5-HT enhanced the responses. At 10(-4) mol l1, 5-HT increased cell input resistance, led to broadening of action potentials and caused increased cell excitability in many AL neurones.
Kloppenburg
P
P
Arizona Research Laboratories, Division of Neurobiology, University of Arizona, Tucson 85721.
Hildebrand
J G
JG
D000200:Action Potentials; D000818:Animals; D001921:Brain / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D005260:Female; D007395:Interneurons / Q000502:physiology; D008297:Male; D018402:Manduca; D009832:Olfactory Nerve / Q000187:drug effects / Q000502:physiology; D009833:Olfactory Pathways / Q000187:drug effects / Q000502:physiology*; D012701:Serotonin / Q000494:pharmacology*; D012903:Smell / Q000502:physiology
D012701:Serotonin