Changes in plasma corticosterone levels as a measure of acute dependence upon levorphanol in rats.

摘要: Changes in plasma corticosterone levels have been utilized as a sensitive and reliable indicator of opiate withdrawal. By using rats prepared with chronic indwelling i.v. catheters, drug injections sequential blood sampling were accompanied conscious undisturbed animals. Acute administration levorphanol tartrate (LT) at 0.5, 1.0 or 2.0 mg/kg b.wt. caused an elevation circulating corticosterone. With the lowest dose LT, hormone returned to pretreatment values by 180 min. Naloxone hydrochloride (NX), 0.4 mg/kg, administered 3 hr after 0.5 produced significant In contrast, animals pretreated saline did not show same increase NX. NX, several doses, along suppressed which is normally observed when LT given acutely. When NX sufficient dosage, pretreatment, subsequent antagonist elicit withdrawal response. These data indicate that similar corticosterone, upon challenge single morphine, generalizes other opiates. Blockade initial rise injection speak probability responses being related specific.