ABSTRACT
This chapter examines the role of neurotransmitter substances in the regulation of Prothoracicotropic hormone (PTTH) cell activities by the culture of isolated brain of the cabbage army worm, Mamestra brassicae. Nialamide, which acts as an inhibitor of monoamine oxidase, and eserine and diisopropylphosphorofluoridate which act as reversible or irreversible blockers of acetylcholinesterase, were used as agonists of the neurotransmitters. All chemicals were dissolved in T. D. C. Grace's medium at appropriate concentrations to investigate their effect either on ecdysone synthesis of the cultured prothoracic glands or on PTTH release from the cultured brain in vitro. The quantity of ecdysone from each culture was determined by ecdysone radioimmunoassay. In Manduca sexta, when either the brain-retrocerebral complex or isolated corpora allata as the PTTH neurohemal organ were subjected to culture, spontaneous release of large amounts of PTTH occurred. The results of PTTH assay against the brain-cultured media suggest that the PTTH released from cultured brains may be a mediated cholinergic neural system.
