Effect of bilateral lesions of the solitary tract nucleus on arterial blood pressure in spontaneously hypertensive rats of Okamoto strain.

Bilateral electrolytic lesions of the solitary tract nucleus in control Wistar albino rats as well as in Okamoto rats with spontaneous arterial hypertension caused a considerable rise in the arterial blood pressure. Quantitative comparison of blood pressure rise in normotensive and hypertensive rats demonstrated that the rise in the systolic and mean blood pressure was not significantly different in both groups of animals. However, the rats with spontaneous hypertension reacted, with a greater rise in the diastolic pressure. A characteristic feature observed in the normotensive rats was a high rise in pulse pressure following lesion of the solitary tract nucleus while in the rats with spontaneous hypertension this change was not found. The authors conclude that increased peripheral vascular resistance in the rats with spontaneous hypertension is not due to inhibition or resetting of the baroreceptor reflex.