Naloxone ameliorates the pathophysiologic changes which lead to and attend an acute stroke in stroke-prone/SHR.

Abstract

Stroke-prone, spontaneously hypertensive rats (SP/SHR) were fed a low protein (8%) fish diet + 1% saline at the time of weaning; some were treated with Naloxone (0.4 mg/100 gms bw/sc/2 X daily/5 days per week). Naloxone-treated animals did not develop high blood pressure or strokes. Sixty-two days after feeding the low protein fish diet, blood pressure levels reached 260-300 mmHg and all of the non-treated animals exhibited acute and severe strokes; Naloxone treatment was again initiated for half of the SP/SHR. By Day 4 (post stroke), all of the non-treated SP/SHR were dead; Naloxone-treated SP/SHR survived until Day 12 (post stroke). Naloxone-treatment during the post-stroke period caused significant reduction of blood pressure, ACTH, and beta-endorphin levels concomitant with reduced cerebral edema and clearance of hepatic lipid infiltration. It is suggested that anti-opiate treatment may ameliorate the severe hypertension-inducing effects of a low protein fish diet and thereby prevent the appearance of strokes in SP/SHR as well as palliate the cerebral edema and fatty liver which characteristically appear in the immediate post-stroke period in fish-fed SP/SHR. The central mechanism of this palliative effect may be through reduced hypothalamic-pituitary-adrenal activity.