Carotid sinus reflex function in the alloxan diabetic rabbit.
Baroreflex function was studied in three groups of adult rabbits. Seven animals were given alloxan (100-200 mg/kg) and became diabetic (group D) with mean blood sugar values of 348 +/- 30 mg/dl. Eight animals were given alloxan, but did not develop significant hyperglycemia (135 mg/dl) (group A). Nine controls (group C) were also studied (glucose, 101 mg/dl). All animals were anesthetized with pentobarbital (30 mg/kg). Blood pressure (BP) and heart rate (HR) responses to bilateral carotid occlusion (BCO) were measured before and after depressor nerve sectioning (DNx) and sinus nerve sectioning (SNx). Before sectioning, BCO caused a rise in BP of 30 +/- 4 mmHg in group C. 35 +/- 3 in group A, and 36 +/- 4 in group D. HR increased about 13 beats/min in each group. After DNx, resting BP increased in group C from 97 to 104 mmHg (P less than 0.005), but no change occurred in the other groups. Responses to BCO were significantly but similarly enhanced in all groups after DNx. HR did not increase in group D. Resting BP increased after SNx only in the controls (group C). Differences in BP elevation with BCO before and after SNx ("pure" reflex response) were identical, averaging about 35 mmHg. Thus, no alteration of BP or HR responses to BCO was identified in early alloxan diabetes. However, resting tone in the buffer nerves may have been less.
D000496:Alloxan; D000818:Animals; D001794:Blood Pressure; D002346:Carotid Sinus / Q000503:physiopathology*; D003714:Denervation; D003921:Diabetes Mellitus, Experimental / Q000503:physiopathology*; D005260:Female; D006339:Heart Rate; D008297:Male; D011817:Rabbits; D012018:Reflex
D000496:Alloxan