Ibotenate
Lesion of the Ventromedial Hypothalamus Lowers
Hyperthermic Effects of Prostaglandin E1
M. MONDA, A. SULLO, V.
DE LUCA, A. VIGGIANO
Department
of Human Physiology and Integrated Biological
Functions "Filippo Bottazzi", Second
University of Naples, Naples, Italy
Received
June 20, 2000
Accepted October 5, 2000
Summary
This
experiment tested the effects of an
intracerebroventricular injection of
prostaglandin E1 on the sympathetic activation
and the thermogenic changes in rats with
ibotenate lesions of the ventromedial
hypothalamus. Under pentobarbital anesthesia,
twelve Sprague-Dawley male rats were lesioned
bilaterally in the ventromedial hypothalamus with
an injection of ibotenic acid (30 nmol into each
side). Sham lesions were carried out in other
twelve control rats. After 48 h, all animals were
anesthetized with ethyl-urethane. The firing rate
of the sympathetic nerves innervating the
interscapular brown adipose tissue and the
colonic and interscapular brown adipose tissue
temperatures were monitored before and after an
intracerebroventricular injection of
prostaglandin E1 (500 ng) or saline.
Prostaglandin E1 induced an increase in the
firing rate of sympathetic nerves and the colonic
and interscapular brown adipose tissue
temperatures. These effects were reduced by the
ventromedial hypothalamic lesion. Since ibotenic
acid destroys cell bodies, the findings indicate
that neurons of the ventromedial hypothalamus
play a considerable role in the control of
sympathetic activation and the thermogenic
changes during prostaglandin E1 hyperthermia.
Key
words
Brown
adipose tissue · Central nervous system ·
Hyperthermia · Pyrogen · Rat · Sympathetic
activity
Reprint
requests
Dr. Marcellino Monda, M.D., Dipartimento di
Fisiologia Umana, Via Costantinopoli 16, 80138
Napoli, Italy, e-mail: marcellino.monda@unina2.it
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