Ghrelin receptor antagonism of morphine-induced accumbens dopamine release and behavioral stimulation in rats.

Rationale And Objectives: Ghrelin, an orexigenic (appetite stimulating) peptide activates binding sites in the ventral tegmental area (a structure linked with the neural reward system) allowing it to participate in reward-seeking behavior. An increasing number of studies over the past few years have demonstrated ghrelin's role in alcohol, cocaine, and nicotine abuse. However, the role of ghrelin, in opioid effects, has rarely been examined.

Codeine did not increase analgesic efficacy of coxibs in contrast to that of paracetamol or ibuprofen: isobolographic analysis in mice.

Objectives: There is good evidence that opioids can potentiate analgesic activity of some older non-opioid analgesics (such as paracetamol or ibuprofen) but it is not known whether this also holds true for newer non-opioid analgesics that selectively inhibit cyclooxygenase 2 (coxibs). This study was undertaken to determine the nature of the interaction between codeine and celecoxib or etoricoxib in peritoneal irritation-induced visceral pain in mice. For comparison, interactions of codeine with paracetamol and ibuprofen were also tested using the same method.

Effects of URB597, an inhibitor of fatty acid amide hydrolase (FAAH), on analgesic activity of paracetamol.

Objectives: Paracetamol is converted to an active metabolite AM404 via fatty acid amide hydrolase (FAAH). The aim of the present study was to ascertain whether a FAAH inhibitor URB597 antagonizes paracetamol analgesic activity (and to asses by this way the role of FAAH in analgesic activity of paracetamol).

Methods: The interaction between a FAAH inhibitor URB597 and paracetamol was investigated in the writhing test in mice using an isobolographic analysis.

Influence on analgesic activity and serum levels after meloxicam complexation with beta-cyclodextrin in mice and rats.

The aim of the present study was to evaluate and compare the analgesic activity and serum levels of meloxicam (CAS 71125-38-7) after administration of meloxicam associated with beta-cyclodextrin (BCD, CAS 7585-39-9) and unmodified meloxicam. The analgesic activity was measured using the plantar test (rats) and the writhing test (mice). In the plantar test, BCD-meloxicam (3 mg/kg and 10 mg/kg orally) showed higher analgesic activity than corresponding doses of meloxicam alone; in the writhing test BCD-meloxicam (7 mg/kg and 15 mg/kg orally) showed stronger analgesic activity than unmodified meloxicam.

Guaifenesin enhances the analgesic potency of ibuprofen, nimesulide and celecoxib in mice.

Objectives: Previously, we found that guaifenesin enhances analgesia induced by paracetamol. The aim of the present study was to determine whether guaifenesin is able to also increase analgesic activity in the non-steroid anti-inflammatory drugs ibuprofen, nimesulide and celecoxib. In addition we investigated the influence of guaifenesin on plasma levels of nimesulide.