RESUMO
It is showed that the activity of paragiganocellularis [PGi] nucleus is diminished in addict animals, but in contrast this activity was augmented during withdrawal period. Also, regarding interrelation of opiate and adenosine systems, it was obvious that in each system not only the specific antagonists but also the contrast antagonists system could produce withdrawal signs. In this study the role of PGi nucleus in precipitation of withdrawal signs induced by opiate and adenosine antagonists was investigated. In this experimental study, dependency was induced by escalating doses of morphine via drinking water which were prescribed to the animals during a 21 days period. Then addicated rate were subjected to four groups: 1-Intact 2-Sham 3-unilateral PGi destruction and 4-bilateral PGi destruction. Withdrawal signs were induced by 1-Naloxone [2 mg/kg sc.] and 2-Caffeine [50 mg/Kg ip.] administration in each group. Data was gathered and then analyzed using one way ANOVA, Tukey and Chi square tests. P< 0.05 was considered significant. Naloxone withdrawal signs were consisted of diarrhea, ejaculation, teeth chattering, ptosis, irritability, wet dog shake, strop tail, jumping and weight loss. Following bilateral PGi destruction there was a marked attenuation in three signs of irritability, teeth chattering and jumping sings. The number of withdrawal signs which were produced by Caffeine administration were less than Naloxone [diarrhea, ejaculation, teeth chattering, chewing, irritability and jumping]. However, destruction of PGi nucleus [bilateral] diminished four sgins including: diarrhea, ejaculation teeth chattering, and irritability. The present study showed that the withdrawal signs precipitated with Caffeine are less different than Naloxone, and the bilateral PGi destruction could markedly attenuate these sings in Caffeine group more than Naloxone ones