ENHANCEMENT BY SEROTONIN OF THE GROWTH IN-VITRO OF ANTENNAL LOBE NEURONS OF THE SPHINX MOTH MANDUCA-SEXTA

Cell culture experiments have been used to examine the effects of sero tonin [5-hydroxytryptamine (5-HT)] on the morphological development of antennal lobe (AL) neurons in the brain of the sphinx moth, Manduca s exta, The majority of cells used in this study were from animals at st age 5 of the 18 stages of metamorphic adult development. 5-HT did not affect the survival of M, sexta AL neurons in culture, but did increas e the numbers of cells displaying features characteristic of certain c ell types. Three morphologically distinct cell types were examined in detail. The principal effect of 5-HT on these neurons was enhancement of cell growth, The magnitude of responses to this amine was cell-type specific. Site-specific responses to 5-HT were apparent also in one c ell type, Our results suggest that the effects of 5-HT can change duri ng the course of metamorphic development. These changes coincide tempo rally with the development of fast, sodium-based action potentials. (C ) 1996 John Wiley & Sons, Inc.