Effect of flumazenil on recovery from anesthesia and the bispectral index after sevoflurane/fentanyl general anesthesia in unpremedicated patients / 대한마취과학회지

BACKGROUND: Benzodiazepines have a hypnotic/sedative effect through the inhibitory action of gamma-aminobutyric acid type A receptor. Flumazenil antagonizes these effects via competitive inhibition, so it has been used to reverse the effect of benzodiazepines. Recently, flumazenil has been reported to expedite recovery from propofol/remifentanil and sevoflurane/remifentanil anesthesia without benzodiazepines. Endogenous benzodiazepine ligands (endozepines) were isolated in several tissues of individuals who had not received benzodiazepines. METHODS: Forty-five healthy unpremedicated patients were randomly allocated to either flumazenil or a control groups. Each patient received either a single dose of 0.3 mg of flumazenil (n = 24) or placebo (n = 21). After drug administration, various recovery parameters and bispectral index (BIS) values in the flumazenil and control groups were compared. RESULTS: Mean time to spontaneous respiration, eye opening on verbal command, hand squeezing on verbal command, extubation and time to date of birth recollection were significantly shorter in the flumazenil group than in the control group (P = 0.004, 0.007, 0.005, 0.042, and 0.016, respectively). The BIS value was significantly higher in flumazenil group than in the control group beginning 6 min after flumazenil administration. CONCLUSIONS: Administration of a single dose of 0.3 mg of flumazenil to healthy, unpremedicated patients at the end of sevoflurane/fentanyl anesthesia without benzodiazepines resulted in earlier emergence from anesthesia and an increase in the BIS value. This may indicate that flumazenil could have an antagonistic effect on sevoflurane or an analeptic effect through endozepine-dependent mechanisms.

Long-term neurotoxic effects of MDMA result in cortical and hippocampal structural changes / 生理学报

3,4-Methylenedioxymethamphetamine (MDMA) is a substituted amphetamine with stimulating and hallucinogenic properties. Since MDMA induces "ecstasy" it is extensively used as a "recreational" drug. It has been well established that MDMA is neurotoxic and can result in long-term degeneration of cerebral 5-hydroxytryptamine (5-HT) nerve terminals in many species. The present study was undertaken to investigate the long-term neurotoxic effects of MDMA on cortical and hippocampal structures, by repeatedly administering MDMA in short time. Male Wistar rats were randomly assigned to control group and MDMA-treated group. MDMA (10 mg/kg) was administered to rats of MDMA-treated group, once per hour, total 40 mg/kg; rats of control group were treated with the same volume of saline. Thirty-two weeks after administering MDMA, the expression of serotonin transporter (SERT) mRNA and diazepam binding inhibitor (DBI) mRNA was detected by in situ hybridization. The expression of glial fibrillary acidic protein (GFAP) was detected by immunohistochemistry, and the degeneration of nerve terminals was demonstrated by Bielschowsky and Glee Marsland silver staining. The results showed that the expression of SERT mRNA in hippocampus decreased by 31.96%, while expression of DBI mRNA in neocortex increased by 40.51%, compared with the control group (P<0.05). The expression of GFAP in the brain tissue increased (P<0.05), while significant reduction of the nerve terminals in neocortex was demonstrated by silver staining, compared with the control group. These results suggest that the neurotoxicity of MDMA results in sustained cortical and hippocampal structural changes, which in turn result in disorder of the brain functions.

Attenuation of the effect of progesterone and 4'-chlordiazepam on stress-induced immune responses by bicuculline.

The present study investigates the effect of progesterone, a pregnane precursor of neurosteroids, and 4'-chlordiazepam (4'-CD), a specific ligand for mitochondrial diazepam binding inhibitor receptor (MDR) involved in neurosteroidogenesis, on restraint stress (RS)-induced modulation of humoral and cell-mediated immune responses. RS produced a significant reduction in anti-sheep red blood cells (SRBC) antibody titre, a measure of humoral immune response, and % leucocyte migration inhibition (LMI) and foot-pad thickness test, measures of cell-mediated immune responses. These effects of RS on immune responses were effectively blocked by pretreating the animals with progesterone (10 mg/kg, sc) or 4'-CD (0.5 mg/kg, sc) administered just before subjecting the animal to RS. The effect of both progesterone and 4'-CD on RS-induced immune modulation was significantly attenuated by bicuculline (2 mg/kg, ip) but not by flumazenil (10 mg/kg, ip). Unlike its effect on RS-induced immune responsiveness, progesterone (5, 10 mg/kg, sc) when administered to non-stressed animals produced a significant suppression of both humoral and cell-mediated immune responses which was not reversed by bicuculline. However, 4'-CD failed to modulate immune response in naive non-stressed animals. These results suggest that progesterone and 4'-CD affect stress-induced immune responses by modulating GABA-ergic mechanism. However, GABA-A receptor system does not appear to be involved in progesterone-induced immunosuppression in nonstressed animals.