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HORMONES AS LONG‐TERM ERROR SIGNALS FOR THE SYMPATHETIC NERVOUS SYSTEM: IMPORTANCE OF A NEW PERSPECTIVE
Author(s) -
Osborn John W.
Publication year - 1997
Publication title -
clinical and experimental pharmacology and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 103
eISSN - 1440-1681
pISSN - 0305-1870
DOI - 10.1111/j.1440-1681.1997.tb01792.x
Subject(s) - endocrinology , medicine , vasopressin , hormone , prazosin , angiotensin ii , reflex , sympathetic nervous system , efferent , blood pressure , renin–angiotensin system , baroreceptor , mean arterial pressure , receptor , afferent , heart rate , antagonist
SUMMARY 1. A hormonal‐sympathetic reflex model for long‐term control of arterial pressure is presented. It is hypothesized that the hormonal‐sympathetic reflex regulates arterial pressure during chronic dietary salt loading by decreasing sympathetic tone. This sympathetic response is mediated by an increase in plasma vasopressin (AVP) and a decrease in plasma angiotensin (AngII). 2. Three new models of neurogenic salt‐dependent hypertension are presented. All models are theoretically based on an impaired hormonal‐sympathetic reflex. 3. In the first model, sympathetic responsiveness is ‘clamped’ by long‐term α‐adrenergic blockade with prazosin. Prazosin treated rats exhibit marked salt‐dependent hypertension despite normal suppression of the renin‐angiotensin system. 4. In the second model, the ability of the central nervous system to respond to salt‐induced changes in AVP and AngII concentrations was prevented by long‐term administration of antagonists selective for the AVP‐V 1 and AT 1 . This ‘clamp’ of the afferent hormonal signal resulted in salt‐dependent hypertension identical in magnitude to that observed in prazosin treated rats. 5. In the third model, the long‐term arterial pressure responses to increasing dietary salt were examined in sino‐aortic denervated (SAD) rats. SAD rats exhibited salt‐dependent hypertension, of lesser magnitude than that observed with ‘clamped’ afferent and efferent pathways of the hormonal‐sympathetic reflex. 6. A primary role for hormonal ‘error signals’ is presented and the impact this perspective has on past and future investigations of central mechanisms of long‐term arterial pressure regulation is discussed.