Calcium channel blockers inhibit the hyperglycemic effect of calcitonin.

We studied the effect of Russian preparation of porcine calcitonin (calcitrin, 1 U/100 g) and blockers of Ca(2+) channels nifedipine (1 mg/kg, blocker of chemosensitive Ca(2+) channels) and isoptin (5 mg/kg, blocker of voltage-dependent Ca(2+) channels) on glucose metabolism. Calcitonin produced a pronounced hyperglycemic effect in rats. A close negative correlation was found between glucose level and total calcium content. Injection of calcitonin reduced glucose tolerance in rats. Isoptin and nifedipine reduced plasma calcium level and did not affect significantly the blood glucose levels, did not change the pattern of alimentary hyperglycemia in response to glucose load, completely abolished the hyperglycemic effect of calcitonin, and prevented calcitonin-induced impairment of glucose tolerance.

[EEG pattern as an instrument for evaluation of neurophysiological mechanisms underlying adaptation disorders].

The method of statistical evaluation of probable interaction between the main constituents of bioelectrical activity of the brain (BEA) enables to reveal the character of intercentral relations both under normal conditions and at adaptation disorders of different severance. Several types of statistic interactions have been revealed between EEG components (SSIC) correlating with normal interrelations between cortex and subcortex, level of preferential involvement of non-specific brain formations (cortex, thalamic, hypothalamic and brain-stem) into the process, and the degree of instability of neuro-dynamic processes. The findings obtained have shown the degree of expression of adaptation disorders to be connected with gradual destruction of "functional nuclear" within alpha-range, amplification of statistical interrelations with beta-EEG and teta-EEG components and formation of pathological nuclear structures within the ranges aforesaid.

Central neurophysiologic mechanisms of the regulation of inhibition.

The neuronal populations of the cuneate nucleus of the midbrain, the medial parabrachial nucleus, the median and magnus nuclei of the raphé, the electrical and local chemical stimulation of which elicits the inhibition of the motor activity of animals, were determined in chronic experiments on freely-moving white male mongrel rats. It was established that when each of the enumerated regions of the brain are stimulated electrically in other zones which elicit motor inhibition, multineuronal responses with a latent period of less than 2.5 msec were recorded. At the same time, multidirectional bilateral changes in muscle tone of the flexors and extensors of the hind limbs are observed in sodium ethaminal anesthetized and unanesthetized animals. The electrolytic destruction of the inhibitory zones of the median raphé nucleus and raphé nucleus magnus blocks the motor inhibition elicited by electrical stimulation of the cuneate nucleus of the midbrain and the medial parabrachial nucleus.