ISSN:
1432-2072
Keywords:
Naltrexone methobromide
;
Water intake
;
Paraventricular hypothalamic nucleus
;
Supraoptic hypothalamic nucleus
;
Opiate antagonist
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract The effects of naltrexone methobromide, a quaternary derivative of the opioid antagonist naltrexone, were investigated on deprivation (24 h)-induced water intake in the unilaterally cannulated rats. Naltrexone methobromide reduced post-deprivational water intake with an ED50 of 7.3 μg when tested at 30 min (peak effect) after intracere-broventricular administration. It also dose-dependently (0.3–10 μg) depressed water intake, with peak effects at 15 min, after microinjection into the paraventricular hypothalamic nucleus and into the supraoptic hypothalamic nucleus. The drug did not produce any other effects on behaviors. The ED50s were 1.4 μg when given into the paraventricular nucleus, and 3.3 μg when given into the supraoptic nucleus, respectively. Although injections of higher doses (1.0, 3.0 and/or 10 μg) of the drug into the preoptic area, zona incerta, and corpus callosum significantly suppressed water intake, other behavioral manifestations, such as rotational behaviors, convulsions, body shakes, head swaying, and/or backward locomotion were manifested simultaneously with the reduction in drinking. When injected into the lateral hypothalamic area, water intake was not significantly affected by the drug. These findings suggest that the paraventricular and supraoptic hypothalamic nuclei are important sites of action in the naltrexone-induced suppression of water intake.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00518177
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