Neuromedins

Introduction

Neuromedins are smooth muscle-stimulating peptides which were isolated from the porcine spinal cord. Typically, neuromedin S is a 36-amino acid neuropeptide found in the brain of humans and other mammals. It is closely related to neuromedin U and produced in the suprachiasmatic nucleus of the hypothalamus. In addition, neuromedins biological activity and sequences are similar to that of known neuropeptides. Moreover, neuromedins are widely distributed in the central nervous system like as other known neuropeptides. Some studies suggest that neuromedins play an important role in the regulation of the function of the adrenal cortex. Thus, numerous neuromedins and their receptors have been localized to cells including the hypothalamic-pituitary-adrenal axis. Meanwhile, neuromedins exert a variety of effect on hypothalamic-pituitary-adrenal axis. A series of neuromedins have been identified as smooth-muscle stimulant peptides through their physiological functions.

Mechanism of action

The mechanism of action of neuromedins on the adrenal cortex may include both direct and indirect effects. For example, neuromedin L and neuromedin K directly stimulate glucocorticoid secretion. However, neuromedin B and Neuromedin N are invalid in this field. At the same time, neuromedin U only have a stimulating effect on rat adrenal cortex. In addition, neuromedins may stimulate adrenocorticotrophic hormone secretion both in vivo and in vitro and enhanced the adrenocorti cotrophic hormone-releasing effect of corticotropin-releasing-hormone. However, neuromedin S may directly stimulate the sympathetic nervous system via output from the circadian oscillator in the suprachiasmatic nuclei and the endogenous neuromedin S may regulate cardiovascular function by activating the sympathetic nervous system.

Application of Neuromedins

Neuromedins play an important role in the regulation of adrenocortical function. Intracerebroventricular injection of neuromedin S in mice increased the heart rate in a dose-dependent manner. The physiological roles of neuromedin U and neuromedin S include regulation of circadian rhythm, an anorexigenic action, an antidiuretic action, and stimulation of oxytocin and vasopressin release. There are increasing number of data strongly suggests a possibility that these neuromedins may involve in the neural communication in mammals.

References

1. Sakamoto, T., Nakahara, K., Maruyama, K., Katayama, T., Mori, K., Miyazato, M., ... & Murakami, N. (2011). Neuromedin S regulates cardiovascular function through the sympathetic nervous system in mice. Peptides, 32(5), 1020-1026.
2. Mori, K., Miyazato, M., Ida, T., Murakami, N., Serino, R., Ueta, Y., ... & Kangawa, K. (2005). Identification of neuromedin S and its possible role in the mammalian circadian oscillator system. The EMBO journal, 24(2), 325-335.
3. Malendowicz, L. K. (1998). Role of neuromedins in the regulation of adrenocortical function. Hormone and metabolic research, 30(06/07), 374-383.