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Biomedical subjects

W Z Traczyk

Publications and source records attributed to W Z Traczyk.

At least 37 records · Page 2Linked to original sources
PubMed1991

Increase of cardiodepressant activity in medium incubating the posterior pituitary lobe in situ during vagal nerve stimulation in rat.

Previous studies have indicated that there is a cardiodepressant factor in the medium incubating the posterior pituitary lobe in situ. The cardiodepressant activity of the medium incubating the posterior pituitary lobe before and during stimulation of the vagus nerves was tested on isolated auricles of the right heart atrium of a two-day-old rat. It was found that the medium incubating the posterior pituitary lobe collected before stimulation decreased the contraction rate of the auricle by 34%, while that collected during the intermittent stimulation of the central ends of the cut vagus nerves caused a decrease of the auricle contractions frequency by 52%. The addition of cholinergic, serotoninergic, histaminergic receptor blockers or prostaglandin synthetase into Ringer-Lock's solution bathing the auricle has no effect on the changes of the contraction rate caused by the incubation medium.

Animals↗
PubMed1990

Hypophysial portal blood flow during preganglionic stimulation of the superior cervical ganglion under condition of systemic arterial blood pressure stabilization in rat.

The presence of hypothalamic hormones in the pituitary portal blood is regarded as the principal factor by which the hypothalamus controls pituitary secretion. In contrast to numerous investigations on hypothalamic hormone release, the regulation of the hypophysial-portal blood flow (HPBF) has been scarcely studied. Hypophysial-portal vessels were exposed according to the Worthington's method [1966]. The 10-min blood samples were collected before and during unilateral or alternative bilateral electrical stimulation of the preganglionic fibers of the superior cervical ganglia (SCG). During blood samples collection the stable systemic arterial blood pressure was maintained by a barostat. The HPBF was estimated according to the determination of the hemoglobin in samples of washed and collected blood from the cut pituitary portal vessels. The mean HPBF was 3.5 microliters/min. Electrical stimulation of SCG. did not change HPBF. This indicates that sympathetic efferents do not participate in the regulation of HPBF under conditions of stabilization of the systemic arterial blood pressure.

Animals↗
PubMed1990

Alteration of brain stem auditory evoked potentials after intracerebroventricular administration of met-enkephalin in rabbits.

Brainstem auditory evoked potentials (BAEPs) were elicited by binaural click stimulation and recorded from the rabbits with chronically implanted electrodes and a cannula for intracerebroventricular injection (i.c.v.). 400 BAEPs were averaged off line. The registration was carried out before and after i.c.v. injection of met-enkephalin (2.5 or 25 nmol), naloxone (20 micrograms), or i.v. injection of morphine (1.0, 2.0, 5.0 mg/kg b.w.). Enkephalin caused shortening of interpeak latency time, naloxone caused its lengthening, while the effect of morphine was not unidirectional. Enkephalin caused increase in the surface area below the negative peaks located in the range of 4.5-7.5 ms from the first positive peak, naloxone caused its decrease while the effect of morphine was also in this respect not unidirectional. It is concluded that opiate receptors are involved in the modulation of the auditory brainstem responses.

Acoustic Stimulation↗
PubMed1985

Arterial blood pressure response in conscious rabbits to administration of C-terminal fragment of substance P into the cerebral ventricles, intravenously and intragastrically.

The blood pressure was measured in the common carotid artery in a cutaneous bridge in conscious rabbits. The synthetic hexapeptide SP6-11 of C-terminal fragment of Arg-Pro-Lys-Pro-Gln-Gln-Phe-Phe-Gly-Leu-Met-NH2 (Substance P) was administered to animals accustomed to the experimental environment in three separate trials: into the cerebral ventricles, intravenously and intragastrically. Introduction of 2 nmol/kg hexapeptide into the cerebral ventricles via a chronically implanted cannula in the lateral ventricle caused an increase in the blood pressure, reaching a peak 10 min after administration. This maximum increase averaged 34.5 mmHg. Intravenous injection of 2 nmol/kg caused after 1 min a rapid fall in the blood pressure, the decrease averaging 42.7 mmHg at this time. Administration of 2 mg/kg into the stomach caused a slight decrease in blood pressure. Although the decrease was only slight it was statistically significant after 10 min.

Analgesics↗
PubMed1982

Oxytocin release from neurohypophysis evoked by preganglionic stimulation of the rat superior cervical ganglion.

1. In male rats under urethane/chloralose anaesthesia the pituitary gland was exposed by transpharyngeal approach. The following methods were applied: (a) posterior pituitary lobe incubation in situ with the anterior lobe removed and the posterior lobe elevated so that only the vessels between the lobe and the meninges are broken, and continuous exchange of the incubation fluid; (b) removal of the entire pituitary and continuous exchange of the fluid washing the cut proximal end of the pituitary stalk. 2. 20 to 30-min samples of incubation or washing fluid were collected for 3-5 hrs and oxytocin was assayed according to Van Dongen and Hays (1966). 3. Preganglionic stimulation of the superior cervical ganglion caused significant increase (ca. 25 times) of oxytocin release from the posterior pituitary lobe. 4. Preganglionic stimulation of the superior cervical ganglion did not alter oxytocin content in the fluid washing the cut proximal end of the pituitary stalk. 5. The sympathetic neurons of the superior cervical ganglia could evoked oxytocin release from the neurohypophysis but did not change its outflow from the hypothalamus to the neurohypophysis.

Animals↗
PubMed1980

Influence of cerebral ventricles perfusion with hexapeptide derivatives of substance P on evoked tongue jerks in rats.

The effects of perfusion through cerebral ventricles with two hexapeptides, C-terminal derivatives of substance P, on evoked tongue jerks (ETJ), were studied on male rats. During perfusion, stimulation of the infraorbital nerve caused retractive movements (ETJ) of the stretched tongue, the amplitudes of which were recorded. The mean amplitudes of ETJ recorded during each 10 min period of perfusion with McIlwain-Rodnight's solution and solution containing hexapeptides were compared. The biologically most active C-terminal hexapeptide derivative of substance P (pyro-Glu6)SP6-11, perfused through cerebral ventricles in a concentration of 5 nmol/ml increased the ETJ. This effect was dose-dependent. A 10 times higher concentration in the perfusion fluid of the less biologically active hexapeptide SP6-11 was not effective. The possibility that substance P, and its active fragments present in the fluid in cerebral ventricles, could modulate the reflex centers in the medulla is discussed.

Animals↗
PubMed1975

Effect of intravenous and intracarotid injections of hypertonic fluids on the release of melanocyte-stimulating hormone from the rat posterior pituitary lobe incubated in situ.

The posterior pituitary lobe of male rats under urethane anaesthesia was incubated in situ. The pituitary gland was exposed by thr transpharyngeal apprach. The posterior lobe remained in neural and partial vascular connexion with the hypothalamus, whereas the anterior lobe was entirely remobed. Incubation fluid was collected and its melanophore-stimulating activity was assayed in hypophysectomized frogs. No effect was observed after the i.v. injection of 1 ml 120 muM-NaC1 with 60 muM-CaC12 or isotonic NcC1 solution. Hypertonic solutions of 5% NaC1 and 25% glucose injected intravenously to the limit of 0-5% of the body weight, transiently enhanced the release of MSH from the posterior pituitary lobe by 66% (significant) and 15% (not significant) respectively. Intracarotid injection of 0-3 ml 5% NaC1 solution resulted in the highest increase (95%) of MSH release.

Animals↗