Insect Neuropeptides

Abstract

The physiological processes regulated by insect neuropeptides are extensive and include growth, development, molting, reproduction, diapause, behavior, color change, ion and water balance, and muscle contraction. Nearly 80 novel insect neuropeptides have been sequenced to date, 10 or so gene sequences have been determined, numerous analogs have been synthesized, and neuropeptide genes have been expressed in vector systems. Investigations into sites of synthesis and release, and tissue specificity and action, continue to reveal complexity in the (classically simple) insect neuroendocrine system. The rapidly increasing knowledge in this area suggests that useful prototypes for the design of selective pest control agents will emerge in the forseeable future.The field of insect neuroendocrinology has expanded rapidly, fostering numerous reviews within the past five years (1-21), including one book entirely devoted to insect neurohormones (22) and one to insect neuropeptides (23). These publications discuss the discovery, physiology, history and chemistry of insect neuropeptides and present potential applications to pest control. These applications may include: blocking neuropeptide synthesis through expression of antisense RNA or inhibition of specific processing enzymes; inactivation of circulating neuropeptides by binding with specific antibodies, antipeptides or by degradation with specific peptidases; disruption of target binding or signal transduction by peptidomimetics; and disruptive expression of natural or modified neuropeptides through baculoviruses or other expression vectors. As suspected in 1988 (4), the number of purified and sequenced insect neuropeptides has continued to increase, and many of the corresponding nucleotide sequences have followed in rapid succession. Nearly eighty novel amino acid sequences for insect neuropeptides have been identified, and novel nucleotide sequences approach ten. This review updates the recent progress in identification of insect neuropeptide structures and their genes and other areas relevant to the development of pest control agents, This chapter not subject to U.S.