Vasopressin and renin responses to hemorrhage in conscious, cardiac-denervated dogs

Abstract

We measured plasma arginine vasopressin (AVP) and plasma renin activity (PRA) during continuous hemorrhage in cardiac-denervated and sham-operated conscious dogs. Hemorrhage produced comparable decreases in aortic pressure, cardiac output, stroke volume, pulmonary arterial pressure, and left and right atrial pressures in each group of dogs. After 10 ml blood/kg body wt had been removed, AVP was increased in sham-operated dogs (P less than 0.05) but not in cardiac-denervated dogs. After 20 and 30 ml blood/kg body wt had been removed, AVP was increased in all dogs, but the response was markedly attenuated in cardiac-denervated dogs. Hemorrhage at 10 and 20 ml/kg caused comparable increases in PRA in each group of dogs. However, at 30 ml/kg hemorrhage the increase in PRA was significantly higher in cardiac-denervated dogs than in sham-operated dogs. Our results suggest that cardiac receptors play a dominant role in mediating the release of AVP during hemorrhage in conscious dogs. In contrast, we found no evidence for a dominant role of cardiac receptors in mediating renin secretion during hemorrhage.

Effects of high altitude and water deprivation on arginine vasopressin release in men

“…These responses may seem inappropriate when we consider the strong relation between P osm and P AVP and the observed changes, or lack thereof, in P osm . P osm is, however, one of only a number of physiological influences on P AVP ; fluctuations in plasma volume and blood pressure are also capable of altering P AVP response (23,27,29). When all three primary stimuli are considered, a clearer view of the observed P AVP response emerges.…”

“…P AVP was determined on samples frozen and maintained at Ϫ190°C in liquid nitrogen until measurement. Radioimmunoassays for P AVP were carried out in triplicate by methods reported previously (27). The source of standard was USP Posterior Pituitary Reference Standard.…”

“…One distinct characteristic of AMS normally seen at altitude is the lack of a diuresis (10,11,26). Arginine vasopressin (AVP) has been implicated in AMS (4, 10) because of its role in reducing free water excretion at the kidney and because of altitude-induced increases in plasma osmolality (3-5), decreases in plasma volume (7,22,25), and increases in blood pressure (5, 21, 28), the three primary determinants of AVP release (23,27,29).Previous research examining the AVP response to altitude, however, does not support a role for AVP in AMS, because different exposures (1,900-5,400 m) of varying durations (3-30 days) have shown no rise in plasma AVP (P AVP ) (16,18,22). The lack of a P AVP response is paradoxical when we consider that altitude significantly alters plasma osmolality (P osm ) (3-5).…”

Renin and Heart Rate Responses to Haemorrhage are Age Dependent in Conscious Lambs

“…Any age-dependent effects of haemorrhage on the biosynthesis or release of these or other vasodilatory factors is not known. In conscious adult sheep (Cameron et al 1984;Block et al 1987), dogs (Wang et al 1983) and monkeys (Arnauld et al 1977), haemorrhage also results in an increase in plasma levels of AVP, during the hypotensive phase of haemorrhage. This suggests that AVP may contribute predominantly to promoting the recovery from haemorrhagic hypotension, playing a less important role in regulating arterial pressure during mild to moderate haemorrhage, at least in adult animals.…”

Inhibiting the rabbit caudal ventrolateral medulla prevents baroreceptor‐initiated secretion of vasopressin.

“…Vasopressin is secreted from the neurohypophysis following haemorrhage or severe hypotension, a reflex originating from baroreceptors within the atria and great vessels (Share, 1974;Wang, Sundet, Hakumaki & Goetz, 1983). Afferent fibres in the IXth and Xth cranial nerves convey baroreceptor information to the nucleus tractus solitarius, whence it reaches vasopressin-secreting neuroendocrine cells in the hypothalamus by an as yet undefined pathway (Clark & Rocha E Silva, 1967;Yamashita & Koizumi, 1979;Kalia & Mesulam, 1980;Spyer, 1982).…”