Endocrine Abstracts

Since earlier publications revealed a prominent and versatile impact of the neuromedin peptide family on several neuroendocrine processes, in the present experiments we focused on the effects of a recently discovered member of neuromedines, neuromedine S on such phenomena as open-field behaviour and hypothalamic-pituitary-adrenal (HPA) activation. The peptide was administered intracerebroventricularly to freely moving rats and 30 minutes later the aforementioned neuronedocrine parameters were investigated. We also investigated the putative effect of neuromedine S on dopamine and GABA release from rat striatal slices in a superfusion system. Our results disclosed that neromedine S has a profound and dose-dependent action on the HPA system, evoking a threefold increase in plasma corticosterone level in a dose of 1 μg. It also activated grooming in a dose of 0.25 μg. The latter action displayed a bell-shaped dose-response curve. However, the neuropeptide does not influenced neither such open field paradigms as square crossing, rearing and defecation nor has an impact on the release of GABA and dopamine. Our results reinforce the hypothesis that, indeed, neuromedines are important regulators of neuroendocrine processes and shed light on the possible functions of the newly described neuromedine S in the central nervous system. It appears, that centrally administered neuromedine S can stimulate such CRF dependent processes as corticosterone release and grooming. However, further experiments are needed to clarify the exact mediation of these processes.