[Structural and functional changes in the right atrium of the rats induced by short- and long-term heat stress].

In acute experiments performed on rats placed in heat-chamber (40 degrees C, 30- and 60-minutes-long exposure), an increase in NADPH-diaphorase (NADPH-d) and succinate dehydrogenase (SDH) activities were found in the neurons of intramural ganglia of the right atrium, while SDH and lactate dehydrogenase (LDH) activities were increased in cardiomyocytes. Hormone-producing cardiomyocytes, containing atrial natriuretic peptide, had numerous large secretory granules under the sarcolemma close to the microvessels. In contractile cardiomyocytes, the signs of early stage of apoptosis were observed including the subsarcolemmal accumulation of small mitochondria and cytoplasmic invaginations into the nucleus. Prolonged heating (37 degrees C, 4 h daily) led to an increased activities of NADPH-d and SDH in neurons of intramural ganglia of the right atrium and of NADPH-d and LDH in cardiomyocytes. Secretory granules in hormone-producing cardiomyocytes were small and reduced in number. Cardiomyocytes showing the signs of the late stage of apoptosis (with nuclear and cytoplasmic condensation) were demonstrated.

Changes in the activity of NO synthase, energy metabolism enzymes, and the ultrastructure of cerebral cortical neurons in a model of transient ischemia.

Experiments were performed on white male Wistar rats under Nembutal-urethane anesthesia. Transient ischemia (10 min) was produced by clamping of the carotid arteries. Some neurons in the parietal area of the cerebral cortex and endotheliocytes in blood vessels showed increases in NO synthesis and in the activity of energy metabolism enzymes (SDH, LDH). Changes in the ultrastructure of some neurons and synaptic formations provided evidence of a state of functional pressure, while changes in others indicated irreversible changes (disturbances in lipid metabolism and destructive changes in the nucleus and cytoplasm).

[Changes in the activity of NO-synthase, energy metabolism enzymes and ultrastructure in neurons of the cerebral cortex in the model of short-term ischemia]. / Izmenenie aktivnosti NO-sintazy, fermentov énergeticheskogo obmena i ul'trastruktury v neironakh kory bol'shogo mozga pri modelirovanii kratkovremennoi ishemii.

Experiments were performed on male Wistar rats under nembutal-urethan anesthesia. Short-time (10 min) cerebral ischemia was induced by bilateral ligation of carotid arteries. This was followed by an increased synthesis of NO and activity of energy metabolism enzymes (SDH, LDH) in a part of neurons of the parietal cortex and in endotheliocytes of blood vessels. The ultrastructural changes of some neurons and synaptic formations indicated functional tension, while in the others the irreversible changes (disturbed lipid metabolism, destructive alterations of the nucleus and cytoplasm) were found.

[Structure and functional changes in the gastric intramural nervous plexus in emotionally stressed rats exposed to low doses of long-term ionizing irradiation and lead]. / Strukturno-funktsional'nye izmeneniia vintramural'nom nervnom spleten ii zheludka pri émotsional'nom stresse u krys, podvergavshikhsia dlitel'nomu deistviiu ioniziruiushchego izlucheniia i solei svintsa v malykh dozakh.

Changes in the catecholamine content in adrenergic fibres, acetylcholinesterase activity, and in the energy metabolism enzymes lactate dehydrogenase and succinate dehydrogenase in neurons of the gastric intramural plexus during emotional stress in rats a day after combined exposure to prolonged (30 days) ionizing radiation in a total dose 1.0 Gy and 0.6 mg/kg lead were studied. A decrease in catecholamines in adrenergic fibres and acetylcholinesterase and lactate dehydrogenase activity in neurons was observed. An enhanced sensitivity of the gastric intramural plexus after the prolonged exposure to small doses of ionizing radiation and lead in conditions of emotional stress was suggested.

[Structural changes in the pelvic plexus in cold stress]. / Izmeneniia struktur tazovogo spleteniia pri kholodovom stresse.

Alterations caused by hypothermal stress in neurons of pelvic plexus in rats were studied histochemically. The increase of catecholamine content in neurons and serotonin--in small intensely fluorescent cells (SIFC), suppression of acetyl cholinesterase activity in neurons were demonstrated after the short-term hypothermal stress leading to moderate hypothermia. Cooling of rats following the preliminary section of pelvic nerves does not prevent the above mentioned changes in neurons and SIFC. The participant of adrenergic nerves and SIFC in peripheral mechanisms of thermoregulation is under discussion.

[A cytophotometric study of the monoamines and energy metabolism enzymes in the neurons of the paravertebral ganglia under cold-induced and emotional stress]. / Tsitofotometricheskoe issledovanie monoaminov i fermentov énergeticheskogo obmena v neironakh paravertebral'nykh gangliev pri kholodovom i émotsional'nom stresse.

The content of monoamines and energy exchange enzymes in neurons of the stellate ganglion (SG) and Th6-Th10 thoracic sympathetic trunk ganglia (TSTG) was studied histochemically using a computer analysis. Intensification of the monoamine fluorescence and energy exchange enzyme activity in SG neurons was found both during cold and emotional stress. Similar changes in TSTG were observed only during hypothermia. A selective activation of neurons of the paravertebral ganglia under different stresses is suggested.

[Microfluorimetric study of adrenergic structures in nerve plexuses of the pelvic cavity of the normal and decentralized cat]. / Mikrofluorimetricheskoe issledovanie adrenergicheskikh struktur v nervnykh spleteniiakh tazovoi polosti koshki v norme i posle detsentralizatsii.

Microfluorimetric technique was used to study catecholamine concentration in small intensely fluorescent (SIF) cells and in adrenergic fibres of the pelvic plexus ganglia and intramural ganglia of the cat urinary bladder and rectum in control and following sympathetic and parasympathetic denervation. Two types of SIF-cells were studied: cells of the first type contained catecholamines and those of the second type--serotonin. Parasympathetic denervation resulted in an increase of SIF-cells which exhibited serotonin fluorescence, and in more intense fluorescence of adrenergic fibres in the pelvic plexus ganglia and intramural ganglia of the urinary bladder, not affecting the intensity of fluorescence of the adrenergic fibres in the intramural ganglia of the rectum. Sympathetic denervation did not alter the fluorescence intensity in SIF-cells and adrenergic fibres in the pelvic plexus ganglia and urinary bladder and led to almost complete disappearance of the adrenergic fibres in the intramural ganglia of the rectum.

[Cytophotometric study of catecholamines and acetylcholinesterase in neurons of the intramural plexus of the urinary bladder of the cat in controls and animals exposed to experimental conditions]. / Tsitofotometricheskoe issledovanie katekholaminov i atsetilkholinésterazy v neironakh intramural'nogo spleteniia mochevogo puzyria koshki v kontrole i pri nekotorykh éksperimental'nykh vozdeistviiakh.

The intramural plexus of the cat urinary bladder was studied with histochemical methods for catecholamines and acetylcholinesterase. Ganglia of the plexus showed differences in the number of neurons (5 to 150 cells). They were adrenergic, cholinergic or mixed. Section of pelvic nerves increased the amount of catecholamines in adrenergic neurons and fibres and decreased the acetylcholinesterase activity. Section of hypogastric nerves did not affect the catecholamine level and acetylcholinesterase activity.

[Ratio of adrenergic and cholinergic structures in the prevertebral sympathetic and parasympathetic ganglia]. / Sootnoshenie adrenergicheskikh i kholinergicheskikh struktur v prevertebral'nykh simpaticheskikh i parasimpaticheskikh gangliiakh.

Histochemical techniques for catecholamines and acetylcholinesterase revealed the ratio of adrenergic and cholinergic neurons in sympathetic (celiac and inferior mesenteric) and parasympathetic (pelvic) plexuses of the abdominal and pelvic cavities. Three types of ganglia were revealed in the pelvic plexus, i.e. cholinergic, adrenergic, and of mixed type. Adrenergic fibers were found in preganglionic nerves both to sympathetic and parasympathetic plexuses. A centripetal transport of catecholamines through axons of adrenergic neurons located in extramural ganglia, was shown.