抄録
The present study was aimed to survey central neurons that might be activated after peripheral administration of apelin-12 (AP12, one of apelin peptide homologues), by examining the distribution of neurons expressing c-Fos protein. AP12 has been known to
The present study was aimed to survey central neurons that might be activated after peripheral administration of apelin-12 (AP12, one of apelin peptide homologues), by examining the distribution of neurons expressing c-Fos protein. AP12 has been known to induce gastric acid secretion as well as other physiological functions such as regulation of circulation. We undertook to clarify which neurons in the central nervous system may express c-Fos protein after intraperitoneal injection of AP12. In the test experiment, AP12 (800 μg/kg) was intraperitoneally injected in Wistar rats. One and a half hours after the injection, rats were perfused with saline and fixed with fixatives. Then the brain was removed and sectioned at 40 μm in thickness. Every fourth section was treated with anti-c-Fos antiserum, and c-Fos protein was immunohistochemically stained using the avidin-biotin complex method. Control rats were injected with saline, and brain sections were processed similarly as described above. It was found that AP12 injected intravenously induced the neural expression of c-Fos protein in several nuclei throughout the brain. In the paraventricular nucleus hypothalamus (PAH), central nucleus amygdala (CEA), lateral hypothalamic area (LH), paraventricular nucleus thalamus (PVT), periaqueductal gray matter (PAG), lateral parabrachial nucleus (Pbl), the complex of solitary tract nucleus (NTS) and dorsal motor nucleus of vagus nerve (DMX), numbers of neurons expressing c-Fos protein were much more in the test experiments than those in the control experiments. These results suggest that AP12 stimulates central neurons that may play a role in the regulation of gastric acid as well as other physiological functions.
