How peptidergic neurons cope with variation in physiological stimulation.
A general scheme for neuropeptide metabolism is outlined and the potential sites of regulation are discussed. Two major sites of regulation are distinguished: transcription which ultimately limits the rate of translation to form the prepropeptide, and post-translational processing steps. The consequences of up-regulation of these steps in response to increased metabolic demand are discussed. An alternative strategy for peptidergic neurons, reliance on a large pool of neuropeptide, is proposed. Data on the response of enkephalin-containing cells to increased levels of stimulation are reviewed. It is concluded that there is good evidence for genomic up-regulation, perhaps in association with regulation of processing. Evidence based on studies on enkephalin-containing amacrine cells in the chicken retina is also reviewed. It is suggested that these cells rely on a large pool of neuropeptide to cope with changes in demand.
Morgan
I G
IG
Visual Sciences Group, Research School of Biological Sciences and Centre for Visual Sciences, Australia.
Chubb
I W
IW
D000818:Animals; D004745:Enkephalins / Q000378:metabolism; D009474:Neurons / Q000502:physiology*; D009479:Neuropeptides / Q000378:metabolism / Q000502:physiology*; D011498:Protein Precursors / Q000378:metabolism; D012160:Retina / Q000166:cytology / Q000378:metabolism
D004745:Enkephalins; D009479:Neuropeptides; D011498:Protein Precursors; C029992:proenkephalin