effects of morphine and nicotine co-administration on body weight, food intake and appetite-regulating peptides in rats

Previous studies in humans and animals have reported that nicotine administration decreases body weight and caloric intake. Opiate and cigarette have been used concomitantly as drug abuse. The aim of the present study was, therefore, to analyze the effect of chronic co-administration of nicotine and morphine on food intake, body weight and on some feeding-associated peptides. All experiments were carried out on male Wistar rats. Animals were randomly assigned to the free-fed and pair-fed control groups, nicotine-and morphine-treated and nicotine plus morphine groups. Morphine sulfate [20 mg/kg for 14 days s.c.] and nicotine [4 mg/kg for 14 days i.p.] were injected to the rats. The serum levels of leptin and neuropeptide Y [NPY] were measured by enzyme immunosorbant assay and radioimmunoassay, respectively. The results showed that nicotine had a greater suppressing effect on total food intake than morphine alone or nicotine plus morphine. Furthermore, chronic injection of nicotine significantly decreased body weight as compared with before injection, while body weight changes were not observed in morphine-treated rats. The mean body weight in the morphine-treated rats was lower than that in the free-fed control animals. The serum level of NPY was decreased just in the nicotine-injected group. A significant decrease in leptin levels was observed in the drug treated and pair-fed groups. In conclusion, morphine modulates the decreasing effect of nicotine on food intake, and it seems that the mechanism underlying the attenuating effects of morphine on the nicotine effects involves mediation, at least in part, by preventing the effect of nicotine on NPY levels

[ effect of mummy on some indices of wound healing in mice]

Mummy was used in traditional medicine as a remedy for inflammation, articular injuries, rheumatism, bone fractures, wounds, and back pains. In a previous research, the healing effects of mummy on rabbit's tibial fracture were studied and the results approved its efficacy. Considering some natives' claim and suggestions of traditional medicine in regard to the effectiveness of mummy on wound healing, the present study was aimed to investigate the effects of mummy on some healing indices of wound. In this experimental study performed on 56 mice, a vertical incision on the back of mice cutting through the complete thickness of skin was performed. The test groups [mummy], and the control groups [normal saline], were compared for some tissue indices of wound healing and the amount of tension needed to tear the cut by using the tensiometer after 3,7,14, and 21 days. Although the average tissue indices of wound healing differed in test and control groups, these differences were not statistically significant. The average of the tensions needed to tear the healed wound in test groups was significantly greater than that in the control groups. The difference between mean number of histological variables and mean necessary tension to tear open the healed wound between the test and control groups indicated the effectiveness of mummy in tensile stretch of wound healing process but its negligible effectiveness on histological indices of wound healing

Effect of GABA[b] agonist and antagonist microinjection into cuneiformis nucleus [CNF] on morphine induced antinociception by formalin test in rat

There are several evidences that show cuneiformis nucleus is involved in nociception. In the present study the effect of intra cuneiformis micro injection of GABA[B] agonist [baclofen] and antagonist [CGP35348] on morphine induced antinociception in rat were investigated. In this expremental study, through canulation of cuneifoprmis nucleus in rat the effect of intra cuneiformis [CNF] microinjection of GABA[B] receptor agonist [baclofen] and antagonist [CGP35348] on morphine -iduced antinociception were investigated by formalin test. Microinjection of morphine [l0 micro g /0.5 micro l/saline] or different doses of baclofen [0.25,0.5,1 micro g per rat] had antinociception in the both first and second phases of formalin test. The response induced by morphine or baclofen in both phases were reduced by CGP 35348. The responses induced by combination of baclofen [1 micro g per rat] and intraperitoneal [ip] injection of naloxan were reduced in both phases of formalin test. Microinjection of CGP35348 alone has produced antinociception in first phase of the formalin test. Morphine with different doses of baclofen did not increase the antinociception effect whereas microinjection of CGP35348 administration significantly increased the antinociception in acute phase. It may be concluded that CNF GABA[B] receptor induced antinociception via opioid receptor in the formalin test

[ study on the effect of intracuneiformis nucleus microinjection of GABAa receptor agonist and antagonist on ant nociceptive effects of morphine by formalin test in rat]

In the present study, the effects of intracuneiformis nucleus microinjection of gamma-aminobutyric acid4 [GABAA] receptor agonist and antagonist on antinociception inducced by morphine were investigated with formalin test in rat. Intracuneiformis nucleus microinjection of morphine [l0 ngr/rat] and Bicuculline [50, 100 ng/rat] induced antinociception in the both first and second phases of formalin test. Muscimol [25, 50, 100 ngr/rat] produced antinociception only in the second phase of formalin test. Morphine in combination with muscimol but not with bicuculline elicited potentiation. The responses induced by muscimol were not affected by bicuculline. The opioid receptor antagonist [naloxone] did not reduce the response induced by muscimol in the both first and second phases of formalin test. It may be concluded that central GABAA receptor stimulation induced antinociception in formalin test. However, the antinociception induced by GABAA receptor agonist may be partly mediated through nucleus cuneiformis opioid receptor mechanisms. The apparent antinociceptive effects of muscimol may be due to its leakage to rostal portion of Cnf and reduction in motion activity, so have no relation to its real antinociceptive effects