Suppressive effects of Rosa damascena essential oil on naloxone-precipitated morphine withdrawal signs in male mice

This research was done to test the effect of Rosa damascena essential oil on withdrawal signs of naloxone-precipitated morphine in male mice. Morphine dependence was induced by injection [IP] three times daily at doses of 50, 50 and 75 mg/kg, respectively, for 3 days. On day 4, after the last administration of morphine, Rosa damascena essential oil was administered at different concentrations [5, 2 and 40%, IP] 30 min before administration of naloxone [5 mg/kg, IP]. The following actions were taken as signs of withdrawal and records taken for jumping as a number and scores of 0 to 3 were given for incidences of grooming, teeth chattering, rearing, writing, diarrhea, wet dog shakes and climbing during a 30 min period. Results showed that different concentrations of Rosa damascena essential oil significantly reduced signs of morphine withdrawal compared to the control group in terms of number of jumps [p < 0.05 and p < 0.01], grooming, teeth chattering, rearing, climbing, wet dog shakes and writhing, but not for diarrhea [p < 0.05]. In conclusion it seems that GABAergic activity induced by flavonoids from Rosa damascena essential oil can alleviate signs of morphine withdrawal, but further studies need to be done to better understand this mechanism

The terrestrial Gastropoda Megalobulimus abbreviatus as a useful model for nociceptive experiments: effects of morphine and naloxone on thermal avoidance behavior

We describe the behavior of the snail Megalobulimus abbreviatus upon receiving thermal stimuli and the effects of pretreatment with morphine and naloxone on behavior after a thermal stimulus, in order to establish a useful model for nociceptive experiments. Snails submitted to non-functional (22°C) and non-thermal hot-plate stress (30°C) only displayed exploratory behavior. However, the animals submitted to a thermal stimulus (50°C) displayed biphasic avoidance behavior. Latency was measured from the time the animal was placed on the hot plate to the time when the animal lifted the head-foot complex 1 cm from the substrate, indicating aversive thermal behavior. Other animals were pretreated with morphine (5, 10, 20 mg/kg) or naloxone (2.5, 5.0, 7.5 mg/kg) 15 min prior to receiving a thermal stimulus (50°C; N = 9 in each group). The results (means ± SD) showed an extremely significant difference in response latency between the group treated with 20 mg/kg morphine (63.18 ± 14.47 s) and the other experimental groups (P < 0.001). With 2.5 mg/kg (16.26 ± 3.19 s), 5.0 mg/kg (11.53 ± 1.64 s) and 7.5 mg/kg naloxone (7.38 ± 1.6 s), there was a significant, not dose-dependent decrease in latency compared to the control (33.44 ± 8.53 s) and saline groups (29.1 ± 9.91 s). No statistically significant difference was found between the naloxone-treated groups. With naloxone plus morphine, there was a significant decrease in latency when compared to all other groups (minimum 64 percent in the saline group and maximum 83.2 percent decrease in the morphine group). These results provide evidence of the involvement of endogenous opioid peptides in the control of thermal withdrawal behavior in this snail, and reveal a stereotyped and reproducible avoidance behavior for this snail species, which could be studied in other pharmacological and neurophysiological studies.

Antídotos de uso reciente

Los antídotos son sustancias cuya función es contrarrestar el efecto farmacológico y tóxico de otras sustancias, teniendo en cuenta la importancia de las medidas generales en el manejo del intoxicado (baño general, emesis, lavado gástrico, carbón activado, catárticos). Cada día aparecen sustancias nuevas con dichas características. En el presente artículo se pretende dar información breve y detallada sobre las propiedades farmacológicas, indicaciones, dosificación, efectos secundarios y contraindicaciones de algunos de uso general (carbón activado, soluciones electrolíticas con polietilenglycol) y principalmente de algunos específicos de uso reciente: flumazenil, fragmentos Fab-antidigoxina, glucagón, naloxona, clonidina, N-acetil-cisteína, azul de metileno, nitrito y tiosulfato de sodio, ácido-2-3-dimercaptosuccínico, penicilina benzatínica, glicopirrolato y S-adenosil-metionina.

Role of opioidergic component in the antihypertensive effect of clonidine.

The role of opioidergic system in the antihypertensive effect of clonidine was investigated in albino normotensive and renal-DOCA-salt hypertensive models of rats. Clonidine (2.5, 5 and 10.0 micrograms/kg, iv) produced a dose-related depressor response. Yohimbine (2 mg/kg, ip) blocked the clonidine-induced responses in both normotensive and hypertensive rats. Naloxone (2 mg/kg, iv) blocked the clonidine-induced depressor responses in hypertensive rats, but not in normotensive animals. Morphine (0.11 mg/kg, iv) produced a depressor response in both normotensive and hypertensive rats. Yohimbine (1 mg/kg, iv) did not affect the hypotensive effect of morphine in normotensive or hypertensive rats, whereas pretreatment with naloxone significantly blocked the hypotensive effect of morphine in both groups of animals. It is concluded that the hypotensive effect of clonidine in hypotensive rats could be due to an opioidergic mechanism since it is blocked by both naloxone and yohimbine.