Search results for "Catecholamine"

Effects of alterations in sympathetic nervous activity on the severity of reperfusion-induced arrhythmias in anaesthetised rats.

1987

The effects of a number of interventions influencing sympathetic nervous activity on the severity of coronary artery reperfusion-induced arrhythmias in anaesthetised rats have been examined. Noradrenaline (0.1 microgram kg-1 min-1) reduced the mortality that usually occurred as a consequence of ventricular fibrillation. Isoprenaline (5 micrograms kg-1) did not significantly affect the severity of reperfusion-induced arrhythmias, although arrhythmias occurring during the 5-min period of ischaemia were exacerbated. The alpha-adrenoceptor antagonist nicergoline (0.25 and 0.5 mg kg-1 min-1) markedly suppressed both the ventricular tachycardia and fibrillation occurring upon release of the occlu…

Evidence for noradrenaline and adrenaline as sympathetic transmitters in the chicken.

1975

1 The concentrations of noradrenaline and adrenaline in various organs, arterial plasma and venous outflow from isolated hearts of adult chickens have been determined. 2 The relative adrenaline concentrations (percentage of the sum of noradrenaline and adrenaline) in the heart (33%), spleen (16%) and brain (26%) were higher than those found in mammalian organs. Chemical sympathectomy by pretreatment with 6-hydroxydopamine caused a decrease of the noradrenaline and adrenaline concentrations in the heart to 20 and 23% and in the spleen to 16 and 29%, respectively. 3 Stimulation of the right sympathetic nerves, infusion of tyramine or infusion of a modified Tyrode solution containing 108mM K+ …

Effects of CGS 10746B on hyperactivity and place preference induced by morphine

2001

The effects of CGS 10746B, a dopamine release inhibitor, on spontaneous locomotor activity, morphine-induced hyperactivity, acquisition of conditioned place paradigm and morphine-induced conditioned place preference (CPP) was evaluated in male mice. In experiment 1, animals treated with CGS 10746B (0.5, 1, 2, 4, 8, 16, 24 and 32 mg/kg), morphine (40 mg/kg) or morphine (40 mg/kg) plus CGS 10746B (0.5, 1, 2, 4, 8, 16, 24 and 32 mg/kg) were placed in an actimeter during a period of 90 min. In experiment 2, animals treated with CGS 10746B (0.5, 1, 3 and 10 mg/kg), morphine (40 mg/kg) or morphine (40 mg/kg) plus CGS 10746B (0.5, 1, 3 and 10 mg/kg) were conditioned following a procedure unbiased …

Fuel selection during short-term submaximal treadmill exercise in the cold is not affected by pre-exercise low-intensity shivering.

2014

Exercise and shivering rely on different metabolic pathways and consequently, fuel selection. The present study examined the effects of a pre-exercise low-intensity shivering protocol on fuel selection during submaximal exercise in a cold environment. Nine male subjects exercised 4 times for 60 min at 50% (LOW) or 70% (MOD) of their peak oxygen consumption on a motorized treadmill in a climatic chamber set at 0 °C with (SHIV) and without (CON) a pre-exercise cooling protocol, inducing low-intensity shivering. Thermal, cardiorespiratory and metabolic responses were measured every 15 min whereas blood samples were collected every 30 min to assess serum nonesterified fatty acids (NEFA), glyce…

Contractile hyporesponsiveness to norepinephrine of forearm veins in chronic renal failure.

2006

Background We recently reported that endothelium-dependent relaxation is impaired in forearm veins from patients with chronic renal failure. However, assessment of responses to norepinephrine remains controversial. We examined the contractile response to norepinephrine in forearm veins from patients on chronic hemodialysis and the role of nitric oxide (NO), prostanoids, and Ca 2+ -activated K + channels in this response. Methods Isometric contraction curves were obtained in rings of forearm vein from 21 dialyzed patients and 12 multiorgan donors in response to norepinephrine (1 nmol/L to 10 μmol/L) or KCl (5 to 100 mmol/L). Results Veins from uremic patients were markedly less responsive to…

Endogenous and exogenous nitric oxide inhibits norepinephrine release from rat heart sympathetic nerves.

1995

Abstract This study was designed to elucidate whether nitric oxide (NO) controls norepinephrine (NE) release from sympathetic nerves of the rat heart. Hearts were perfused in the Langendorff mode with Tyrode’s solution. The right sympathetic nerve was stimulated with trains of 1 or 3 Hz and NE release was measured. The NO synthase (NOS) inhibitor N G -nitro- l -arginine (L-NNA) enhanced the evoked NE release in a concentration-dependent manner. This facilitation was independent of the increase in perfusion pressure and was stereospecifically reversed by l -arginine but not d -arginine. Another NOS inhibitor, N G -methyl- l -arginine, produced a similar increase in NE release. The NO-donor …

Bilateral olfactory deprivation reveals a selective noradrenergic regulatory input to the olfactory bulb.

2001

Unilateral olfactory deprivation in the rat induces changes in the catecholaminergic system of the olfactory bulb. Nevertheless, evidence suggests that unilateral deprivation does not fully prevent stimulation of the deprived bulb. The present report analyses the response of the catecholaminergic system of the olfactory bulb in fully deprived rats obtained by bilateral naris occlusion. The complete deprivation produces more rapid and dramatic changes in both the intrinsic and extrinsic catecholaminergic systems of the olfactory bulb. Intrinsic responses involve a rapid decrease in dopamine-containing cells to about 25% of controls, correlated with a decreased Fos expression in juxtaglomerul…

Prevention and Management of Hormonal Crisis during Theragnosis with LU-DOTA-TATE in Neuroendocrine Tumors. A Systematic Review and Approach Proposal.

2020

Neuroendocrine tumors (NETs) frequently overexpress somatostatin receptors (SSTR) on their cell surface. The first-line pharmacological treatment for inoperable metastatic functioning well-differentiated NETs are somatostatin analogs. On second line, Lu-DOTA-TATE (177Lu-DOTA0 Tyr 3 octreotate) has shown stabilization of the disease and an increase in progression free survival, as well as effectiveness in controlling symptoms and increasing quality of life. The management of functional NETs before and during LU-DOTA-TATE treatment is specially challenging, as several complications such as severe carcinoid and catecholamine crisis have been described. The aim of this review is to establish pr…

Histamine inhibits spontaneous activity of the uterus of the progesterone-treated rat

1993

Cardiovascular effects of the methanol and dichloromethanol extracts fromTeucrium cartaginenses L.

1998

Methanol and dichloromethanol extracts of the leaves and stems of Teucrium cartaginensesL. have been tested for their effects on resting arterial blood pressure, heart rate and noradrenaline induced hypertension. Both extracts administered i.v. to urethane anaesthetized normotensive rats reduced mean arterial blood pressure and heart valve, while only the dichloromethanol extract prevented noradrenaline induced hypertension. © 1998 John Wiley & Sons, Ltd.