AJP - Regulatory, Integrative and Comparative Physiology, Vol 242, Issue 3 220-R226, Copyright © 1982 by American Physiological Society
Glucose and endocrine responses to hypothalamic electrical stimulation in rats
P. U. Dubuc, L. S. Leshin and P. L. Willis
The effect of ventromedial (VMN) or basolateral (LHA) hypothalamic
electrical stimulation on glucose and hormone production was examined in
conscious and anesthetized male rats. Barbiturate treatment alone led to
large increases of corticosterone and smaller but significant increases of
glucose, insulin, and glucagon. When hypothalamic stimulation was combined
with anesthesia, interactions between the hypothalamic sites and the
awake-anesthetized conditions were observed. This was most evident with LHA
placements, as awake rats exhibited mild hypoglycemia and hypoglucagonemia
in response to low-level (approximately 10 microA rms) current, but no
effects on these values were seen with VMN electrodes. With barbiturate
anesthesia, the same level of stimulation led to severe hyperglycemia in
both VMN and LHA rats and a mild hyperglucagonemia in the LHA group. No
consistent effects of stimulation on immunoreactive insulin or
corticosterone were detected at either hypothalamic site or in any
anesthesia condition. The present results point out the important role
anesthetics may play in studies defining functional aspects of the
hypothalamus. Furthermore, our inability to elicit consistent autonomic
responses with electrical stimulation, when compared with the effectiveness
of both metabolic agents and pharmacologic stimuli, suggests that the sites
integrating autonomic function may be diffusely distributed over the basal
diencephalon.
