Behavior and cellular evidence for propofol-induced hypnosis involving brain glycine receptors.

BACKGROUND: It is well documented that several general anesthetics, including propofol, potentiate glycine receptor function. Furthermore, glycine receptors exist throughout the central nervous system, including areas of the brain thought to be involved in sleep. However, the role of glycine receptors in anesthetic-induced hypnosis has not been determined. METHODS: Experiments were conducted in rats where the loss of righting reflex (LORR) was used as a marker of the hypnotic state. Propofol-induced LORR was examined in the presence and absence of strychnine (a glycine receptor antagonist), GABAzine (a gamma-aminobutyric acid A receptor antagonist), as well as ketamine (an antagonist of N-methyl-D-aspartic acid subtype of glutamate receptors). Furthermore, the effects of propofol on the currents elicited by glycine and gamma-aminobutyric acid were analyzed in neurons isolated from the posterior hypothalamus of rats. The effects of strychnine and GABAzine on propofol-induced currents were also evaluated. RESULTS: Strychnine and GABAzine dose-dependently reduced the percentage of rats exhibiting LORR induced by propofol. Furthermore, strychnine significantly increased the onset time and reduced the duration of LORR induced by propofol. In contrast, strychnine did not affect the LORR induced by ketamine. In addition, propofol markedly increased the currents elicited by glycine and GABA of hypothalamic neurons. Conversely, strychnine and GABAzine both profoundly attenuated the current induced by propofol. CONCLUSION: Strychnine, the glycine receptor antagonist, dose-dependently reduced propofol-induced LORR in rats and propofol-induced current of rat hypothalamic neurons. These results suggest that neuronal glycine receptors partially contribute to propofol-induced hypnosis.

[Clinical observation on treatment of chronic suppurative otitis media caused large tympanic membranes perforation by ear-dropping with combined Chinese and Western drugs].

OBJECTIVE: To observe the therapeutic effect of the self-prepared ear dropping made by combined Chinese and Western drugs in treating chronic suppurative otitis media caused large tympanic membrane perforation. METHODS: Sixty-four patients were randomly divided into two groups, the treated group treated with the self-prepared ear-dropping and the control group treated with ear-dropping made by placebo, to observe the therapeutic effect and adverse reaction. RESULTS: In the 32 patients of the treated group, 15 patients were cured, the cured tympanic membrane was normal in shape and thickness in 11, scarred in 3, and thin and transparent in 1. The hearing was improved in all patients with cured tympanic membrane. But no one was cured in the control group. CONCLUSION: The self-prepared ear-dropping had good effect in treating tympanic membrane perforation, it is simple, cheap and no need of further operation.

[The effect of tripterygium wilfordii polyglycosidium on the compound action potential of skeletal muscle in experimental animals with myasthenia gravis].

OBJECTIVE: To observe and analyze the direct effect of tripterygium wilfordii polyglycosidium (TWP) on the activity of skeletal muscle in experimental animals with myasthenia gravis (EAMG). METHODS: C57BL/6 mice were used. After sieving EAMG animals, we observed and compared the variation of the attenuation percentage of compound action potential of gastrocnemius muscle and pronator teres muscle of EAMG before and after the muscle specimens being immersed in the breeding ground of TWP solution. Such variation of attenuation percentage was taken as an indicator of the direct effect of TWP on skeletal muscle. RESULTS: 1. Evident influence of TWP on the attenuation percentage of compound action potential of gastrocnemius muscle was observed (P < 0.05), and apparent decrease of the attenuation percentage could be seen one and a half hours after the muscle was immersed [(14 +/- 36)% before treatment, (-40 +/- 24)% after treatment]; 2. The influence of TWP on the attenuation percentage of compound action potential of pronator teres muscle was noted (P < 0.05), and an apparent decline of the attenuation percentage could be observed one and a half hours after the muscle was immersed[(17 +/- 25)% before treatment, (-17 +/- 10)% after treatment]; 3. There was no distinctive difference between the gastrocnemius muscle and pronator teres muscle in respect of their attenuation percentages of compound action potential. CONCLUSION: TWP has direct remedial effect on the activity of skeletal muscle of EAMG.

[The effect of TWP on the reactivity of AChR on the end-plate membrane of frog sartorius].

OBJECTIVE: To study the effect of Tripterygium Wilfordii Polyglycosidium (TWP) on the reactivity of n-Acetylcholine receptor (nAChR) on the end plate membrane. METHODS: Using the microionophoretic method, we applied the exogenous acetylcholine chloride (AChCl) to the superficial end-plates of the isolated nonuniform stretched frog sartorius, and acetylcholine potential (AChP) recorded was taken as an indicator of the reactivity of the nAChR in the end plate. RESULTS: 1. After the addition of TWP, the apparent change of AChP was recorded at 20 min in the 20 mg/L group, and at 10 min in the 40 mg/L and 60 mg/L groups respectively. 2. Within the 20 mg/L and 40 mg/L TWP groups, the change in amplitude of AChP showed significant difference with the time (P < 0.05), the greatest being at 60 min. 3. In the 60 mg/L TWP group, action potential was recorded at 40 min, 60 min and 80 min. 4. There was significant difference in the percentage of AChP amplitude change between the three concentration groups (P < 0.05), and the highest percentage of change appeared in the 60 mg/L group. CONCLUSION: TWP can increase the reactivity of nAChR in the end plate membrane, and there exist an apparent concentration-effect relationship and a certain time-effect relationship.

[Effects of TWP on capacity of muscle contraction].

OBJECTIVE: To investigate the direct effects of Tripterygium Wilfordii Polyglycosidium (TWP) on capability of muscle contraction. METHODS: Using electronic stimulator to stimulate the phrenic nerve of the isolated phrenic nerve diaphragm preparation of 30 rats or directly stimulate the isolated gastrocnemius muscle preparation of 45 toads in vitro, we studied the effects of TWP on capability of muscle intrinsic contraction. RESULTS: TWP in 20 mg/L increased the amplitude of muscle contraction in initial 60 min but did not make further increase of the amplitude of muscle contraction from 60 min to 90 min in the isolated phrenic nerve diaphragm preparation of rat under one-third optimal stimulus. TWP in 40 mg/L and in 60 mg/L did not cause decrease of amplitude of muscle contraction in initial 60 min in isolated phrenic nerve diaphragm preparation of rat under one-third optimal stimulus. TWP in 60 mg/L did not cause decrease of tension of signal-contraction in initial 30 min in isolated gastrocnemius muscle preparation of toad under one-third optimal direct stimulus. Solvent DMSO could obviously reduce the tension of muscle contraction both in isolated phrenic nerve diaphragm preparation of rat and in isolated gastrocnemius muscle preparation of toad under one-third optimal stimulus. CONCLUSION: TWP can limitedly enhance the capability of muscle contraction; Solvent DMSO can restrain muscle contraction.