Why the study?
Does graded haemorrhage alter plasma renin activity in conscious rats, and is this response affected by indomethacin or propranolol?
Does graded haemorrhage alter plasma renin activity in conscious rats, and is this response affected by indomethacin or propranolol?
The conscious cannulated rat model demonstrates a predictable, volume-dependent renin response to haemorrhage that is attenuated by combined beta-blockade and cyclooxygenase inhibition.
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Cautions against extrapolating rat haemorrhage-renin findings to patients; leaves open mechanistic roles of beta-adrenergic and prostaglandin pathways.
A haemorrhage volume/plasma renin activity (PRA) response relationship was established for five levels of acute haemorrhage ranging from 1.5 to 15 ml/kg in conscious rats. In addition, the effects of chronic indomethacin and/or acute propranolol administration on the PRA response to 5 and 10 ml/kg haemorrhage was assessed. 2. Mean arterial pressure decreased in a haemorrhage volume dependent manner which was not significantly altered by indomethacin and/or propranolol. 3. Haemorrhage volumes of 1.5 and 3.0 ml/kg did not significantly alter PRA. At haemorrhage volumes of 5.0 ml/kg and higher, PRA increased in a volume-dependent manner. Propranolol decreased basal PRA levels but had little effect on the response to haemorrhage. Indomethacin had no effect on basal PRA, but attenuated the response to haemorrhage somewhat. When propranolol and indomethacin were combined, the PRA response to haemorrhage was significantly attenuated. 4. The conscious cannulated rat model exhibits predictable and reproducible renin responses to haemorrhage and is an excellent model for studying the control of renin secretion.
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Roarty et al. (1988) studied this question.
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