Changes in brain somatostatin and vasopressin levels after stress in spontaneously hypertensive and Wistar-Kyoto rats.
Somatostatin (SRIF) and vasopressin (AVP) were measured in hypothalamic and extrahypothalamic areas in normotensive Wistar-Kyoto (WK) and in spontaneously hypertensive, adult rats (SRH) under control conditions and after acute immobilization stress. Hypothalamic areas included the median eminence (ME) and the periventricular, suprachiasmatic, paraventricular, supraoptic, ventromedial and dorsomedial nuclei. Extra-hypothalamic areas included the striae medullaris, striae terminalis (N. Interst.), locus coeruleus, central gray, Areas 1 and 2 (NTS), and circumventricular organs. Under basal conditions, SHR and WK rats did not differ in their content of SRIF and AVP for most areas examined. After acute stress, however, striking differences were found in peptide content. Somatostatin content was not changed in SHR, but was significantly decreased in most areas in WK rats. On the contrary, generalized increases in AVP content were found in SHR after stress, with no changes in WK animals. An exception was the ME, which showed a decrease in peptide levels in both groups of rats. These results suggest that both hypothalamic and extra-hypothalamic AVP and SRIF are involved in the central stress response. The different changes in peptide levels observed for SHR and normotensive rats after acute stress further support the hypothesis of a role of both AVP and SRIF in central regulation of cardiovascular function.
D000818:Animals; D001127:Arginine Vasopressin / Q000378:metabolism*; D001794:Blood Pressure; D001921:Brain / Q000378:metabolism*; D007031:Hypothalamus / Q000378:metabolism; D008297:Male; D051381:Rats; D013004:Somatostatin / Q000378:metabolism*; D013312:Stress, Physiological / Q000378:metabolism*
D001127:Arginine Vasopressin; D013004:Somatostatin