Article date: 1992/8/1
PubMed ID: 1510167
Journal name: The American journal of physiology (ISSN: 0002-9513)
To determine the role of the nucleus tractus solitarius (NTS) in the tonic maintenance of arterial pressure (AP) following chronic baroreceptor denervation, the present study examined the effect of inhibition of the NTS on AP in chronic sinoaortic denervated (SAD) and control rats. One to two weeks after complete SAD (no residual arterial baroreceptor reflexes) mean AP was not significantly different from that of control rats. Bilateral microinjections of muscimol and lidocaine into the NTS markedly increased AP in alpha-chloralose-anesthetized control rats. However, microinjections of these neuroinhibitory drugs had no effect on AP in SAD rats. Similarly, 1 h after bilateral destruction of the NTS conscious control rats were hypertensive, while AP in SAD rats was not changed. Plasma levels of vasopressin (VP), which were also elevated in control rats 1 h after NTS lesions, were not significantly altered in SAD rats. These results demonstrate that inhibition of the NTS has no effect on AP or plasma levels of VP in chronic SAD rats. This suggests neither the NTS nor afferents to the NTS supply a tonic inhibitory influence on AP after chronic baroreceptor denervation.
Author List: Schreihofer A M, Sved A F
Publication Types: Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S.
Substances mentioned in the article: Saline Solution, Hypertonic; Vasopressins; Muscimol; Lidocaine;
Mesh terms: Animals; Blood Pressure/drug effects; Denervation; Lidocaine/pharmacology; Male; Medulla Oblongata/physiology; Microinjections; Muscimol/pharmacology; Rats; Saline Solution, Hypertonic/pharmacology; Sinus of Valsalva/physiology; Time Factors; Vasopressins/blood;