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Evidence for a renomedullary vasodepressor hormone
C J Thomas1, R L Woods, R G Evans
1Baker Medical Research Institute, Prahran, Victoria, Australia.
Clinical and Experimental Pharmacology & Physiology
|September 1, 1996
Summary
The kidney releases a vasodepressor substance from the renal medulla when blood pressure increases. This newly identified substance, potentially a lipid, helps lower arterial pressure but its exact mechanisms and control require further study.
Area of Science:
- Physiology
- Renal Medicine
- Cardiovascular Research
Background:
- Increasing renal perfusion pressure triggers the release of a vasodepressor substance from the renal medulla.
- This substance is distinct from known mediators like platelet-activating factor, prostaglandins, or nitric oxide.
- The vasodepressor response is not solely attributable to the inhibition of renin release.
Purpose of the Study:
- To investigate the physiological mechanisms underlying the release and action of a novel renomedullary vasodepressor substance.
- To identify the cellular source and chemical nature of this substance.
- To elucidate its role in regulating arterial pressure and its potential involvement in hypertension.
Main Methods:
- Physiological experiments involving manipulation of renal perfusion pressure.
- Pharmacological interventions to rule out known vasoactive substances and pathways.
- Assessment of the substance's effects in animals with blocked autonomic ganglia.
Main Results:
- A vasodepressor substance is released from the renal medulla in response to elevated renal perfusion pressure.
- The substance's effects persist even when autonomic ganglionic transmission is blocked, suggesting partially non-neuronal mechanisms.
- Renomedullary interstitial cells are the likely source of the substance, which may be lipid in nature.
- The release threshold is near normal arterial blood pressure.
Conclusions:
- The renal medulla releases a vasodepressor hormone in response to increased perfusion pressure.
- The precise mechanisms by which this substance lowers arterial pressure, its complete identification, and regulatory control remain to be determined.
- Further research is crucial to understand this hormone's physiology and its potential contribution to the development of hypertension.