RT Journal Article SR Electronic T1 Central sites of naloxone-precipitated shaking in the anesthetized, morphine-dependent rat. JF Journal of Pharmacology and Experimental Therapeutics JO J Pharmacol Exp Ther FD American Society for Pharmacology and Experimental Therapeutics SP 480 OP 487 VO 195 IS 3 A1 E Wei A1 S S Sigel A1 H H Loh A1 E L Way YR 1975 UL http://jpet.aspetjournals.org/content/195/3/480.abstract AB Naloxone hydrochloride, an opiate antagonist, administered via the intracranial or parenteral route precipitates shaking behavior in the morphine-dependent rat. We made localized bilateral injections of naloxone HCl, 1.5 mug/rat, into 60 subcortical sites of the pentobarbital-anesthetized, morphine-dependent rat and found that two circumscribed areas of the brain, the medial hypothalamus and the periaqueductal-4th ventricular spaces, were selectively sensitive to naloxone-precipitated shaking. In the nondependent rat, morphine injections into the anterior diencephalon inhibited the shaking response to ice water; injections of morphine into the medial diencephalon were less effective. However, naloxone antagonized the morphine-inhibited shaking more effectively when injections of naloxone were made in the medial diencephalon than when injections were made in the anterior diencephalon. These results suggest that the reciprocal relationship of morphine and morphine-naloxone effects on shaking behavior may be regulated by topographically different structures in the diencephalon.