Search results for "NERVE"

Effects of (+)-tubocurarine on [3H]acetylcholine release from the rat phrenic nerve at different stimulation frequencies and train lengths

1987

The effect of (+)-tubocurarine (TC) on the release of [3H]acetylcholine from the rat phrenic nerve-hemidiaphragm preincubated with [3H]choline was investigated at different stimulation frequencies and train lengths. At 0.5 Hz (100 pulses) TC failed to modulate the evoked acetylcholine release. A slight (30%) inhibition was observed at 1 Hz (100 pulses). Release of acetylcholine evoked at 5, 25 and 50 Hz (100 pulses) or 100 Hz (200 pulses) was markedly reduced by TC. The degree of inhibition (60%) was similar between 5 Hz and 100 Hz. A concentration of 1 mumol/l TC was a maximal effective concentration at 5 Hz whilst at all higher stimulation frequencies a 10-fold higher concentration was ne…

Über den Einfluss von Acetylcholin auf das Membranpotential denervierter Rattenzwerchfelle

1957

The membran potential of isolated rat-diaphragms has been measured by means of intracellular micro-electrodes, in order to study changes of the resting potential and of the depolarizing action of acetylcholine after section of the phrenic nerve. Within 80 days after denervation, the membrane potential was found to fall exponentially from 87 mV to 66 mV. The action of acetylcholine, on the other hand, was found to be independent of the duration of denervation: between the 4th and the 80th day of denervation: 10−5g/ml acetylcholine always caused the membrane potential to fall by an average of the 9 mV.

Über «therapeutische» und «toxische» Digitoxigeninwirkungen auf elektrophysiologische Messgrössen des Meerschweinchenvorhofs

1963

‘Therapeutic’ concentrations of digitoxigenin (10−7−3× 10−7 g/ml), producing positive inotropic effects, did not alter resting and action potentials of electrically driven guinea-pig auricles. However, ‘toxic’ concentrations of digitoxigenin (5 × 10−7−10−8 g/ml), producing arrhythmias and contracture of the myocardium, had a marked influence upon resting and action potentials and conduction velocity.

Time course of excitatory and inhibitory states of bulbar respiratory modulated neurons.

1980

In respiratory modulated neurons of rabbits, vagally mediated inhibition is not bound to resting membrane potential oscillations. Latency of spinally evoked antidromical spike invasion, however, is shorter and threshold voltage is lower during the shift of membrane potential towards depolarization accompanying burst discharge.

Die Noradrenalin-Abgabe aus dem isolierten Kaninchenherzen bei sympathischer Nervenreizung und ihre pharmakologische Beeinflussung

1962

Der Einfluss von Acetylcholin auf die42Kalium-Abgabe postnataler, denervierter und reinnervierter Skeletmuskulatur

1960

The loss of42K from the isolated rat diaphragm into the bathing solution is increased by acetylcholine, (a) 3 to 4 days after birth, (b) 7 to 14 days after sectioning of the phrenic nerve. The42K loss is not altered by acetylcholine in the diaphragm of adult rats and after the denervated diaphragm has become reinnervated.

Die Wirkung von Reserpin auf die Konzentration von Adrenalin und Noradrenalin im Katzenherz

1959

1. Cats were given single injections of 1.8 mg/kg reserpine intraperitoneally. After a time interval of 18 hours the animals were killed. The concentration of adrenaline and noradrenaline in the right and left atria and ventricles was estimated by a method reported previously. 2. Reserpine caused a similar loss of catechol amines from all parts of the heart. The concentration of noradrenaline was reduced by 93–97%, the concentration of adrenaline by 59–79%. 3. These observations suggest that the adrenaline of the heart behaves differently from that of sympathetic ganglia or postganglionic nerve fibres after an injection of reserpine. In ganglia and nerve fibres the adrenaline concentration …

Functional consequences of prejunctional receptor activation or blockade in the iris.

1994

The iris is innervated by nerves of the sympathetic, parasympathetic, and sensory nervous systems. The terminal nerve fibres are endowed with prejunctional receptors which modulate neurotransmitter release. Activation or blockade of prejunctional receptors by drugs may have an influence on iris smooth muscle tone. Several findings are in favour of the hypothesis that prejunctional receptors may be involved in regulation of iris smooth muscle tone and/or pathophysiological events. (i). Release of acetylcholine from parasympathetic nerves of guinea-pig iris sphincter evoked by electrical stimulation is subject to autoinhibition via prejunctional M2 muscarinic receptors, and the release can be…

Temperature dependence of the toxic effects of phenytoin on peripheral neuromuscular function of the rat tail.

1990

We studied the acute effects of a single dose of phenytoin (250 mg/kg) on peripheral neuromuscular function. The evoked muscle action potentials of the dorsal segmental muscles in the rat tail, and the conduction velocity of the dorsal nerve trunk which innervates them, were measured before and after the intraperitoneal injection of phenytoin. The experiments were performed at different temperatures, 27 (physiological tail temperature), 36 and 37 degrees C (physiological central temperature) in different groups of animals. The amplitudes of the evoked muscle action potentials in the treated groups showed no significant modifications at 27 degrees C, at 36 degrees C a small nonsignificant de…

Prevention of the acute neurotoxic effects of phenytoin on rat peripheral nerve by H7, an inhibitor of protein kinase C.

1992

Abstract The neurotoxic effects of a single dose of phenytoin (150 mg/kg body weight) alone or 30 min after H7 (a protein kinase C inhibitor) injection (20 mg/kg body weight) were investigated in terms of peripheral neuromuscular function and Na + ,K + -ATPase activity of the sciatic nerve. This intraperitoneal injection of phenytoin induced complete blockade of muscle action potentials in the dorsal segmental muscles of the rat tail evoked by electric stimulation of the caudal nerve and a 40% decrease in the Na + ,K + -ATPase activity of the rat sciatic nerve when compared with control values, measured as the difference between total and ouabain-insensitive ATPase activity. Prior administr…