Hypertension and sympathetic nervous system overactivity rely on the vascular tone of pial vessels of the rostral ventrolateral medulla in spontaneously hypertensive rats

2019 ◽  
Vol 105 (1) ◽  
pp. 65-74 ◽  
Author(s):  
Milene R. Malheiros‐Lima ◽  
Vagner R. Antunes ◽  
Ana C. Takakura ◽  
Thiago S. Moreira
Keyword(s):  
Nervous System ◽  
Sympathetic Nervous System ◽  
Spontaneously Hypertensive Rats ◽  
Vascular Tone ◽  
Rostral Ventrolateral Medulla ◽  
Ventrolateral Medulla ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Pial Vessels ◽  
Sympathetic Nervous

Role of the sympathetic nervous system in the alcohol–guanabenz hemodynamic interaction

1992 ◽  
Vol 70 (9) ◽  
pp. 1217-1224 ◽  
Author(s):  
Abdel A. Abdel-Rahman ◽  
Robert G. Carroll ◽  
Mahmoud M. El-Mas
Keyword(s):  
Nervous System ◽  
Sympathetic Nervous System ◽  
Spontaneously Hypertensive Rats ◽  
Specific Interaction ◽  
Plasma Catecholamines ◽  
Hypotensive Effect ◽  
Plasma Catecholamine ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Sympathetic Nervous

The present study evaluated the contribution of the sympathetic nervous system to the adverse hemodynamic action of ethanol on hypotensive responses in conscious unrestrained spontaneously hypertensive rats. Ethanol caused a dose-related attenuation of the hypotensive effect of guanabenz. An equivalent hypotensive response to sodium nitroprusside was not influenced by ethanol, which indicates a potential specific interaction between ethanol and guanabenz. Alternatively, it is possible that a preexisting high sympathetic nervous system activity, which occurred during nitroprusside infusion, may mask a sympathoexcitatory action of ethanol. Further, ethanol (1 g/kg) failed to reverse the hypotensive effect of the ganglionic blocker hexamethonium. This suggests that a centrally mediated sympathoexcitatory action of ethanol is involved, at least partly, in the reversal of hypotension. In addition, the antagonistic interaction between ethanol and guanabenz seems to take place within the central nervous system and involves opposite effects on central sympathetic tone. Finally, changes in plasma catecholamines provide supportive evidence for the involvement of the sympathetic nervous system in this interaction. In a separate group of conscious spontaneously hypertensive rats, ethanol (1 g/kg) reversed the guanabenz-evoked decreases in blood pressure and plasma catecholamine levels. It is concluded that (i) ethanol adversely interacts with centrally acting antihypertensive drugs through a mechanism that involves a directionally opposite effect on sympathetic activity, and (ii) a sympathetically mediated pressor effect of ethanol is enhanced in the presence of an inhibited central sympathetic tone.Key words: spontaneously hypertensive rats, ethanol, catecholamines, guanabenz, hexamethonium.

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