نقش گيرنده هاي آلفا- 2 آدرنرژيك هسته پاراژيگانتوسلولاريس جانبي بر برخي علايم قطع مصرف مرفين در موش صحرايي نر

The role of alpha-2 adrenergic receptors of lateral paragigantocellularis on morphine withdrawal syndrome signs in male rat

The role of alpha-2 adrenergic receptors of lateral paragigantocellularis (LPGI) in morphine withdrawal syndrome was investigated in male rat. For dependence induction, morphine was injected at doses of 25, 30, 35 and 40 mg/kg (i.p.) twice a day for a period of four days. Withdrawal syndrome was induced through injection of naloxone hydrochloride (2 mg/kg; i.p.). For behavioral evaluation, number of chewing, jumping, paw tremors, standing on feet, ejaculation, and defecation was visually recorded for 30 min after naloxone injection. In addition, 0.5 µl of two different doses of clonidine (containing 2 and 4µg/µl of the drug) as an alpha-2 adrenoceptor agonist was bilaterally injected into LPGI 5 min following naloxone injection. The results showed that clonidine administration attenuated number of chewing, jumping, and paw, augments standing on feet, and had no effect on ejaculation and defecation. It seems that some signs of morphine withdrawal syndrome in relation to LPGI arc influenced by alpha-2 adrenergic system.