در هسته لوكوس سروليوس بر علايم قطع مصرف القاج شده به وسيله نالوكسان در موش هاي بزرگ آزمايشگاهي نر وابسته به مورفين D1 اثرات تزريق عوامل دوپامينرژيك گيرنده هاي

The effects of intra-locus coeruleus injection of dopamine D1 receptor agents on naloxone-induced withdrawal signs

Opiate-induced addiction is one of the main problems of mankind societies and its treatment is one of the health priorities of community. Therefore, relative studies would be very crucial. The exact mechanism of dependence to opiates and their withdrawal syndrome remain unclear. It seems that dopaminergic system and locus coeruleus (LC) have an important role in the somatic signs expression of opioids withdrawal syndrome. In the present study, the effects of different DI dopaminergic receptor agonist and antagonist administration into the LC on the expression of withdrawal signs of morphine dependence in rats were studied. Rats were divided into 8 groups (n=8). Two cannulae were stereotaxically implanted bilaterally into the LC. After 1 weak recovery, 7 groups rendered dependent to morphine (subcutaneously) during a 7 day period and non-dependent animals were received saline with the same protocol. Animals received bilateral intra-LC injections of saline, SKF38393 (D1 agonist) or SCH23390 (D1 antagonist) before naloxone injection about 24 hours after the last dose of morphine or saline. Total withdrawal score as an index of withdrawal syndrome were decreased by SKF38393 (2, 4 vg/site) but not by SCH23390. It is concluded that the D1 dopaminergic system in the LC may be involved in the morphine induced dependency in rats.