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W Kuschinsky

Publications and source records attributed to W Kuschinsky.

120 records · Page 7Linked to original sources
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Local glucose utilization and local blood flow in hearts of awake rats.

Local cardiac glucose utilization and local cardiac blood flow in rat heart were measured in vivo by quantitative autoradiographic techniques with 2-[14C] deoxyglucose and [14C] iodoantipyrine, respectively. [14C]methylmethacrylate standards were calibrated for quantitative autoradiography of dried sections of heart tissue; the calibration values for heart tissue differed from those for brain by 8%, probably because of differences in self-absorption within the tissues. The lumped constant required by the deoxyglucose method was determined in isolated, perfused, working rat hearts and found to be 1.11 +/- 0.36 (mean +/- SD, n = 21). The heart: blood partition coefficient for iodoantipyrine required by the [14C]iodoantipyrine method was measured and found to be 1.25. The results obtained in awake rats showed: 1) overall cardiac glucose utilization varied considerably among animals with a mean of 53 (left ventricle) and 30 (right ventricle) mumol/100 g/min; 2) cardiac blood flow was less variable among animals with a mean of 592 (left ventricle) and 420 (right ventricle) ml/100 g/min; 3) glucose utilization was found to be particularly high in the papillary muscle; 4) systematic gradients of glucose utilization or blood flow in the ventricular wall were not observed; 5) glucose utilization and blood flow were not closely correlated on a local level. It is concluded that autoradiographic methods are suitable for the quantification of local glucose utilization and local blood flow in the rat heart in vivo. These methods could not demonstrate transmural gradients for glucose utilization and blood flow between epi- and endocardium in awake rats.

Animals↗
PubMedDate not supplied

In vivo effects of alpha-adrenoceptor agonists and antagonists on pial veins of cats.

Cerebral blood volume and intracranial pressure may be modified by influences on cerebral veins. The known adrenergic innervation of cerebral veins and their sensitivity to norepinephrine raised the question, whether pial veins can be selectively influenced through adrenoceptors in vivo. Therefore, alpha 1 and alpha 2 adrenoceptor agonists and antagonists were locally injected into the perivascular space of pial veins using the microapplication technique. The alpha 1 and alpha 2 adrenoceptor antagonists, prazosin and yohimbine, had only minor effects on pial veins. Both antagonists blocked constrictions induced by norepinephrine (10(-5)M) in a concentration dependent manner (10(-7)-10(-4)M). The alpha 1 adrenoceptor agonist phenylephrine caused significant (10(-7)-10(-3)M) constriction of pial veins, with a maximum of 11.6% of initial diameter at 10(-3)M. Oxymetazoline, an alpha 2 receptor agonist, induced a significant constriction only at 10(-3)M (5.1%). Since both alpha 1 and alpha 2 adrenoceptor agonists are less potent constrictors of pial veins than norepinephrine in vivo, a preferential use of alpha 1 or alpha 2 adrenoceptor agonists cannot be recommended from these experiments, if a therapeutic reduction of intracranial pressure or blood volume is desired.

Adrenergic alpha-Agonists↗
PubMedDate not supplied

Coupling of blood flow and metabolism in the brain.

Blood flow and metabolism are locally heterogeneous in the brain, but tightly coupled. This adjustment occurs in two different ways: (1) short-term, dynamic coupling mediated by local vasoactive factors that ensure second-to-second regulation; (2) long-term, static coupling, apparently mediated by capillary density and developed in response to local functional and metabolic activity. Recognizing these two mechanisms permits one to distinguish apparent from real uncoupling. It allows the conclusion that there is no indication of an uncoupling of metabolism and blood flow during physiological conditions.

Animals↗