Search results for "morphine"
showing 10 items of 145 documents
Lack of Specific Effects of Selective D1 and D2 Dopamine Antagonists vs. Risperidone on Morphine-Induced Hyperactivity
2000
Abstract RODRIGUEZ-ARIAS, M., I. BROSETA, M. A. AGUILAR AND J. MINARRO. Lack of specific effects of selective D 1 and D 2 dopamine antagonists on morphine-induced hyperactivity. PHARMACOL BIOCHEM BEHAV 66 (1) 189–197, 2000.—In the present study, three different dopamine antagonists were challenged in order to counteract hyperactivity induced by 50 mg/kg of morphine. A wide range of doses of morphine (50, 25, 12.5, 6.25, or 3.12 mg/kg) were evaluated on spontaneous locomotor activity. A significant increase was observed only with the two higher doses tested (25 and 50 mg/kg). No decrease was found with any of the doses used at any period of time. After analyzing doses of SCH 23390 (0.5, 0.1,…
Isolation decreases physical and motivational aspects of morphine withdrawal
2005
Environmental manipulations such as social housing conditions of animals may play a role in the expression of individual differences in response to drugs. This study aimed to evaluate whether isolated and grouped mice develop different degrees of morphine dependence. Isolated and grouped mice were rendered morphine dependent employing two different methods of induction: a fast or slow protocol, both reaching the same maximum daily dose (100 mg/kg). Naloxone-induced morphine withdrawal was assessed using a modified Gellert-Holtzman scale and a conditioned place aversion (CPA) procedure. Isolated animals manifested fewer signs of physical dependence than grouped mice and only those receiving …
The effects of dopamine D 2 and D 3 antagonists on spontaneous motor activity and morphine-induced hyperactivity in male mice
1999
Rationale: Dopaminergic neurotransmission, in particular the mesolimbic pathway, is involved in spontaneous locomotor activity and in morphine-induced hyperactivity, since the drugs acting on DA receptors can modify the action of morphine and this effect could be dependent on the type of DA receptor affected. Objective: In this study, the action of U-99194A maleate, haloperidol, sulpiride and morphine (5, 10, 20, 40 mg/kg) on locomotor activity in male mice was evaluated. Likewise, the effects of these dopaminergic antagonists on morphine-induced hyperactivity were studied. Methods: Animals treated with U-99194A maleate (2.5, 5, 10, 20 mg/kg), haloperidol (0.075, 0.1 mg/kg), sulpiride (20, …
Effects of SCH 23390, Raclopride, and Haloperidol on Morphine Withdrawal-Induced Aggression in Male Mice
1999
Abstract RODRIGUEZ-ARIAS, M., J. PINAZO, J. MINARRO AND L. STINUS. Effects of SCH 23390, raclopride, and haloperidol on morphine withdrawal-induced aggression in male mice. PHARMACOL BIOCHEM BEHAV 64(1) 123–130, 1999.—Dopamine seems to play a very important role in aggressive behavior observed in morphine withdrawal. The effect of SCH 23390 (0.5 mg/kg), raclopride (0.3 mg/kg), and haloperidol (0.1 mg/kg) on morphine withdrawal-induced aggression has been studied in this work. Mice were rendered dependent by a daily injection of morphine (2.5 mg/kg) for 14 days. Three different experiments were carried out with the objective to evaluate the antiaggressive effect of the dopamine antagonists o…
The use of pilocarpine in opioid-induced xerostomia
2001
Oral dryness can be a symptom of asystemic disease, an adverse effect of anticholin-ergic, antiadrenergic or cytotoxic drug treatment, orit can be due to local radiotherapy. Opioid use isstrongly associated with xerostomia, although themechanism for this remains unclear; in one studypatients receiving morphine were four times morelikely to have a dry mouth than patients taking otherdrugs known to cause xerostomia.
Modulation by opioids and by afferent sensory neurones of prostanoid protection of the rat gastric mucosa.
1992
1. Pretreatment with capsaicin, to deplete sensory neuropeptides from primary afferent neurones or the administration of morphine (9 mg kg-1, i.v.), which can inhibit neuropeptide release, augmented gastric mucosal injury induced by a 5 min challenge with intragastric ethanol in the rat, as assessed by macroscopic and histological evaluation. 2. Morphine administration substantially attenuated the protective actions of the prostaglandin analogue 16,16 dimethyl prostaglandin E2 (dm PGE2; 0.5-20 micrograms kg-1, p.o.) against ethanol-induced damage. This reduced degree of protection by dmPGE2 was not however, the consequence of the enhanced level of damage. 3. These actions of morphine in red…
Investigation of an opioid response categorization in advanced cancer patients
1999
The aim of this study was to investigate a possible distinction in three categories of opioid response and to identify possible factors associated with a poor response. A prospective survey was carried out in 105 consecutive patients requiring morphine for at least 4 weeks before death. Mean pain intensity, opioid doses and symptom intensity at weekly intervals, pain syndromes, and the presence of psychological distress were assessed. Opioid escalation index (OEI%) was calculated from the parameters recorded. Three categories were considered, including (1) patients with slow increments of opioid dose and a mean analgesic 10-cm visual analogue scale (VAS) less than 4 (responders), (2) patien…
The effects of diazepam on the behavioral structure of the rat's response to pain in the hot-plate test: Anxiolysis vs. pain modulation
2011
The aim of the present study was to evaluate, by means of quantitative and multivariate analyses, the effects of diazepam on the behavioral structure of the rat's response to pain in the hot-plate test as well as whether such changes are associated with drug-induced effects on anxiety and/or nociception. To this purpose, ten groups of male Wistar rats were intraperitoneally injected with saline, diazepam (0.25, 0.5 and 2 mg/kg), FG-7142 (1, 4 and 8 mg/kg) or morphine (3, 6 and 12 mg/kg). The mean number and mean latency to first appearance were calculated for each behavioral component. In addition, multivariate cluster and adjusted residual analyses based on the elaboration of transition ma…
Ineffectiveness of dextromethorphan in cancer pain
1998
Experimental studies have indicated that N-methyl-D-aspartate (NMDA) receptor antagonists may be effective analgesics in a wide variety of chronic pain states. The mechanism is presumed to be related to decreased firing of dorsal horn neurons after constant repeated C-fiber stimulation. Dextromethorphan (DM), a potent NMDA antagonist with a good safety profile, may be a promising agent for the treatment of persistent pain. An open-label randomized trial was designed to examine the effects of combining DM with NSAIDs, dextropropoxyphene, or morphine in cancer patients with pain. Patients who required a change in the step of the World Health Organization's (WHO) analgesic ladder because of a …
Safety and effectiveness of intravenous morphine for episodic (breakthrough) pain using a fixed ratio with the oral daily morphine dose
2003
Breakthrough pain is normally severe in intensity and has a rapid onset. The availability of supplemental doses of opioids (rescue medication) in addition to the continuous analgesic medication is the main treatment suggested to manage these pain flares. The intravenous (i.v.) route may provide analgesia fast enough, but has never been assessed in clinical studies. The aim of this open-label study was to verify the safety and effectiveness of an i.v. dose equal to one-fifth the calculated equianalgesic total daily dose in advanced cancer patients with episodic pain. A consecutive sample of 48 cancer patients treated with oral morphine, who reported an acceptable basal analgesia and reported…