Desensitization of nicotinic receptors / 中国药理学通报

Nicotinic acetylcholine receptors, a ligand-gated ion c hannels,mediates many important physiological processes. Chronic nicotine admini stration could desensitize nicotinic receptors. Many factors which modulate dese nsitization have been described, including different subunits, agonist, signal t ransduction and cellular microenivornment. The important physiological functions of desensitized receptors still remain controversial, may be modulate synaptic transmission,synapse plasticity and mediate self-protection.

Antidepressant Activity of Extract of Hypericum perforatum with Enriched Flavonoids / 中药新药与临床药理

Objective To investigate the antidepressed effects of the extract of Hypericum perforatum with enriched flavonoids. Methods The forced swimming test( FST) , tail suspension test( TST) , open field activity( OFA) test and reserpine- induced hypothermia test were carried out to determine the antidepressant activity in mice. Mice immobility duration in FST and TST , spontaneous activity frequency in OFA , and body temperature decrease in reserpine antagonistic test were observed.Results Extract at the dosages of 40, 80, 160 and 240 mg/kg dosage except the dosage of 20 mg/kg, could significantly shorten mice immobility time in FST and TST.Extract could reduce mice spontaneous activity frequency to some degree in OFA. Compared with the model group, extract at the dosages of 30, 60 and 120 mg/kg could remarkably inhibit the decrease of body temperature in reserpine antagonistic test at 3rd, 4th and 5th hour, so did the extract at the dosages of 240 and 480 mg/kg. Conclusion Extract of Hypericum perforatum with enriched flavonoids (free of hyperforin) exerts an antidepressant activity in animal models.

Effects of Iptakalim hydrochloride on brain damage and blood rheology after focal cerebral ischemia in rats / 中国药理学通报

Aim To investigate the therapeutic effects of Iptakalim hydrochloride on brain damage and blood rheological changes induced by focal cerebral ischemia. Methods The rat model of focal cerebral ischemia was induced by middle cerebral artery occlusion using a suture method. Infarct size was evaluated by TTC staining. Neurological deficit score was evaluated by Longas method. Cerebral water content of the ischemic hemisphere was measured using wet-and-dry-weight method. The erythrocyte membrane fluidity was studied by the fluorescence polarization technique with DPH fluorescence probe. Results Infarct size of the brain was (24.75?6.66)% of contralateral hemisphere 6 h after focal cerebral ischemia.Pretreatment of Ipt 1.0～4.0 mg?kg -1,given inperitoneal,decreased the infarct size by 0.95%,6.6%(P