Effects of carnosine on amygdaloid-kindled seizures in Sprague-Dawley rats.

The effects of carnosine (beta-alanyl-L-histidine) on amygdaloid-kindled seizures were investigated in rats. I.p. injection of carnosine (500, 1000, 1500 mg/kg, i.p.) significantly decreased seizure stage, afterdischarge duration and generalized seizure duration, and significantly prolonged generalized seizure latency of amygdaloid-kindled seizures, in a dose-dependent, and time-related manner. The protective effect of carnosine (1500 mg/kg) was completely antagonized by histamine H1-antagonists pyrilamine (2, 5 mg/kg, i.p.) and diphenhydramine (5, 10 mg/kg, i.p.), but not by histamine H2-antagonist zolantidine even at a high dose of 10 mg/kg. Carnosine (1500 mg/kg, i.p.) caused a significant increase of carnosine and histidine levels in the hypothalamus, thalamus, hippocampus, amygdala and cortex, as well as histamine levels in the hippocampus and amygdala. I.c.v. injection of alpha-fluoromethylhistidine (50 microg, i.c.v.), a selective and irreversible histidine decarboxylase inhibitor, only partially reversed the inhibition of amygdaloid-kindled seizures induced by carnosine. In addition, carnosine significantly decreased glutamate contents in the amygdala and hippocampus. These results indicate that carnosine could protect against amygdaloid-kindled seizures in rats, and its action may be due to the activation of histamine postsynaptic H1-receptors via two different mechanisms, one being carnosine's direct action, and the other being indirectly mediated by histaminergic pathway. The study suggests that carnosine may be an endogenous anticonvulsant factor in the brain and could be used as a new antiepileptic drug in the future.

[Comparative study of menstruation in 240 healthy women at various altitudes].

To assess the relation of menstrual physiologic functions and altitudes, the authors made a comparative study of 240 healthy women with four diagnostic methods on traditional Chinese medicine and obtained their menstrual changes, picture of tongue and type of pulse in Xining (2260m) and Yushu Zhaduo (4300m). The results suggested that the menarche which occurred before 15 years old (P less than 0.005), the menstruation cycle of 16-25 days (P less than 0.05), and moderate quantity menstruation (P less than 0.005) are found more in the Xining group than in the Zhaduo group; the menstrual phase in the Xining group lasted 4-7 days and 1-3 in the Zhaduo group. The incidence of abdominal pain, cold, and lumbago increased significantly in the Zhaduo group and the symptoms were serious. The age of menostasia after 46 was 100% in the Xining group, whereas 27.3% of the Zhaduo group had menostasia at the age of 36-45. The colour of tongue varied from darker red to pink with increasing altitudes (P less than 0.005). Meanwhile, cases of rapid pulse increased (P less than 0.005). It is concluded that the physiology of menstruation for healthy women has obviously changed under high altitude hypoxic environment. The mechanism of pathology could be explained by dysfunction of Zang and Fu, deficiency of Qi, stagnation of blood and Qi stasis due to cold. Treatment and prevention of menstrual disorders of women at high altitudes could be carried out by invigorating Qi, regulating blood, promoting the flow of Qi, by warming the channel and regulating Zang and Fu, etc.

Auditory spatial response areas of single neurons and space representation in the cerebellum of echo locating bats.

Using free-field acoustic stimulation conditions, we studied the auditory spatial response areas of 242 cerebellar neurons of Eptesicus fuscus. A best frequency stimulus was delivered from a loudspeaker which was moved across the frontal auditory space in order to determine the response center of each cerebellar neuron. At the response center, the neuron had its lowest minimum threshold. The stimulus was then raised 5-15 dB above the lowest minimum threshold of each neuron and the spatial response area for each stimulus intensity was measured. The spatial response area of each neuron expanded asymmetrically with the stimulus intensity. The size of the spatial response area was not correlated with the minimum threshold, best frequency or recording depth of the neuron. The distribution of the best frequencies of single neurons was not correlated with their recording depths or minimum thresholds. The response centers of all cerebellar neurons were located within a small area of the central portion of the frontal auditory space suggesting that the cerebellum could play an effective role in orienting the bat toward the echo source within the frontal gaze during insect capture.