SummaryWe have demonstrated in a rat model that the intrathecal injection of 0.02ml of 6.3% magnesium sulphate, a concentration iso-osmolar with rat plasma, will produce a state of spinal anaesthesia and general sedation, lasting approximately 1 h. These effects reversed completely after 6 h, without evidence of neurotoxicity, immediately or during the period 1 week following the injection. The accompanying changes in haemodynamic and respiratory functions were minimal throughout the period of anaesthesia and compare favourably with those induced by an intrathecal bolus of 0.04 ml of 2% lignocaine.

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4 mg kg −1 ) as an intrathecal bolus, provides intraoperative anaesthesia, comparable with that produced Gamma hydroxybutyric acid, a central inhibitory by intrathecal lignocaine. We demonstrated that neurotransmitter and a cerebral metabolite of gammagamma hydroxybutyrate, given by an intrathecal bolus aminobutyric acid, is present in high concentrations in the rat model, produced reversible segmental antiin the mammalian hypothalamus and basal ganglia. nociception, together with muscular relaxation of the Its sodium salt gamma hydroxybutyrate has been abdominal wall and rear limbs. This is accompanied effectively used as an intravenous anaesthetic agent, by moderate sedation without haemodynamic or resand as an oral sedative, and in the management of piratory depression. This agent may thus be promising the alcohol withdrawal syndrome. In an animal model, for use as a spinal anaesthetic drug. using 72 Wistar strain rats allocated to one of six groups of 12 animals each, with implanted lumbar Keywords: gamma-aminobutyric acid; gamma intrathecal catheters, we examined whether gamma hydroxybutyrate; spinal anaesthesia, rat model, hydroxybutyrate, 20% 40 L (32 mg kg −1 ) administered intravenous anaesthetics. alone or combined with fentanyl, gamma hydroxybutyrate 20% 20 L (16 mg kg −1 ), fentanyl 0.005% 20 L been used orally to treat the effects of alcohol with-