The role of gamma-aminobutyric acid in the inhibiting action of emotional stress on the sexual activity of mice

Experiments on male mice of A/He strain have shown that an increase in the level of gamma-aminobutyric acid (GABA) or emotional stress block an increase in the blood level of testosterone caused by the presence of a recipient female mouse. Under the conditions of sex activation the blockade of GABAA-receptors eliminates partially the inhibitory effect of emotional stress on androgen function of a single male or a micropopulation of animals. A conclusion is that the inhibitory effect of emotional stress on the blood level of testosterone during sex activation is achieved through the GABAergic mechanism by means of excitation, at least partially, of GABAA-receptors. The revealed mechanism can play an adaptive role in stress under natural conditions.     

The oxygen-transport function of blood in reconstructive operations on the aorto-femoral segment and application of high molecular hydroxyethyl starch

The prospective randomized investigation included 71 patients with obliterating atherosclerosis of the lower extremities with chronic ischemia. Planned operations of aorto-bifemoral shunts were made. Patients of the first group (n=43) were treated by infusion therapy including solutions of colloids and crystalloids. In the second group a solution of high molecular hydroxyethyl starch was used in addition to colloids and crystalloids. Transfusion of the allogenic components of blood was made in the both groups according to the indications. The parameters of the oxygen-transport function of blood were studied before initial narcosis, under conditions of general anesthesia before the beginning of operation, in 60 minutes of reperfusion after finishing the aorto-femoral shunting, and in a day after operation. It was shown that using the solution of high molecular hydroxyethyl starch promoted the elevated level of the delivery and consumption of oxygen as compared with the standard infusion-transfusion therapy which is explained by the predominantly hemodynamic component of the oxygen transport.     

Impact of Multidetector CT on 3D CT Angiography

3D Computed Tomographic Angiography (CTA) is a noninvasive volumetric imaging technique increasingly used for evaluation of vascular system. The introduction of Multidetector CT (MDCT) has increased scanning speed, allowing shorter acquisition time, greater volume coverage and decreased contrast requirement while diminishing respiratory motion artifacts. Thin-slice collimation protocols are routinely used which generate isotropic 3D voxels that improve image quality. The ideal CTA study requires scanning at peak vascular enhancement for optimal opacification of arteries with separation of arteries and veins. MDCT has enabled complete lower extremity inflow and runoff studies with a single injection, as well as thin-section CTA covering the entirety of the Carotid arteries and Circle of Willis. Sixteen row MDCT has increased scanning speed further facilitating the development of novel applications such as coronary CTA. CTA when perfomed with MDCT offers a “one scan – many views” option useful in imaging vascular diseases. CTA has important advantages over conventional angiography, such as reduced risk, diminished time and better patient acceptance. With MDCT, 3D CTA is crossing vessel tortuosity and evaluation of vessel fragility.Key Words: Multidetector CT, CT angiography, Volume Rendering     

Role of gamma-aminobutyric acid in the activation of the pituitary-testicular complex of mice induced by the presence of a female

Conclusions Thus, the accumulation of GABA in the organism after the administration of an inhibitor of -ketoglutatrate-GABA transaminase blocks the rise in the testosterone level in the peripheral blood plasma of male mice induced by the presence of a receptive female. The inhibiting effect of the blocker of GABA metabolism depends on the genotype of the animal. When a, receptive female is encountered under normal conditions, the inhibiting effect of GABA is not manifested, since neither blockage of the GABA receptors by bicuculline nor a decrease in its content in the organism after the administration of the glutamate decarboxylase inhibitor TSC has any effect on the rise in the testosterone level in the blood during sexual excitation.It has been suggested that the GABAergic mechanism inhibits sexual excitation of the male when he encounters a receptive female only under conditions of stress.Translated from Problemy Éndokrinologii, Vol. 33, No. 4, pp. 48–51, July–August, 1987.     

Dopamine receptors of the diencephalon associated with the endocrine function of the hypophyseal-testicular system]

One hour after local administration of 1 gamma of dopamine into the medial portion of the subthalamus or into the central grey matter of the caudal portion of the thalamus of male Wister rats testosterone level (determined fluorimetrically) more than doubled in the peripheral blood plasma. A similar effect was produced by apomorphine (2 gamma), stimulant of dopamine receptors, administered into the same areas of the diencepalon. No increase in testosterone content followed local administration of dopamine into the arcuate nuclei of the hypothalamus. A conclusion was drawn that dopamine receptors of the diencephalon associated with the endocrine function of the male gonad were located in the medial portion of the subthalamus and in the area of the central grey matter of the posterior portion of the thalamus. At the same time, dopamine neurons of the arcuate nuclei of the hypothalamus apparently took no part in the regulation of the endocrine function of the hypophysio-testicular system.