5-Hydroxy-tryptamine modulates pheromone-evoked local field potentials in the macroglomerular complex of the sphinx moth Manduca sexta.
Extra- and intracellular recordings from an intact brain preparation were used to study the effects of 5-hydroxytryptamine (5-HT or serotonin) on projection neurons in the sexually dimorphic macroglomerular complex (MGC) in the antennal lobe of the male moth Manduca sexta. The MGC is a group of three identified glomeruli specialized for synaptic processing of primary afferent information about the multi-component sex pheromone of the female. We investigated the modulatory effects of 5-HT on pheromone-evoked local field potentials in the MGC. The magnitude and duration of these potentials, which are thought to be generated by a population of pheromone-sensitive projection neurons of the MGC, were increased by 5-HT. Using intracellular recordings from the neurites of individual MGC projection neurons, we found that 5-HT increased the number of action potentials in response to pheromonal stimulation. These findings correlate well with earlier experiments that used other recording techniques. Our results are further evidence that 5-HT modulates a population of pheromone-sensitive MGC projection neurons that relay information about the pheromonal stimulus from the MGC to higher-order centers in the protocerebrum and are therefore pivotal for mate-finding and odor-guided behavior.
Kloppenburg
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P
Arizona Research Laboratories, Division of Neurobiology, University of Arizona, Gould-Simpson Building, Tucson, AZ 85721, USA. pk29@cornell.edu
Heinbockel
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T
D000818:Animals; D005071:Evoked Potentials / Q000187:drug effects; D005260:Female; D008297:Male; D018402:Manduca / Q000187:drug effects / Q000502:physiology*; D009420:Nervous System / Q000187:drug effects; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D010675:Pheromones / Q000494:pharmacology*; D012701:Serotonin / Q000494:pharmacology*
D010675:Pheromones; D012701:Serotonin