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The characteristics of the hyperpolarization response to acetylcholine (ACh) in endothelial cells from the guinea pig coronary artery were studied by microelectrode recording technique. ACh (30 nM to 3 microM) induced membrane hyperpolarization in a dose-dependent manner. The sustenance of the response required the presence of external calcium. The(More)
1. The response of rat tail arteries to stimulation of perivascular nerves was studied with intracellular micro-electrodes. 2. E.j.p.s were recorded from all smooth muscle cells. With higher stimulus strength, a slow depolarization that lasted for more than 30 sec also appeared. Repetitive stimulation was more effective in eliciting this slow component than(More)
Membrane rectification to depolarization was studied by voltage recording with patch electrodes in freshly isolated cells from the rat tail artery. Injection of depolarizing currents elicited electrotonic potentials that developed with a single-exponential time course (time constant of 94.8 ms). When the cell was depolarized beyond −30 mV, delayed(More)
1. The frequency, amplitude and time course of spontaneous excitatory junction potentials (s.e.j.p.s) and their relationship to the time course and amplitude of evoked excitatory junction potentials (e.j.p.s) were examined. 2. The frequency and amplitude of s.e.j.p.s varied dramatically between cells. There was good correlation between their rise and decay(More)
Contraction of the guinea pig saphenous artery induced by stimulation of perivascular nerves consists of an adrenergic and a purinergic component. Neuropeptide Y (NPY) potentiated the neural responses significantly at low stimulation frequencies but not at high frequencies when the contraction was maximal. After blocking the adrenoceptors with phentolamine,(More)
The effect of adenosine on Ca(2+)-dependent K(+) currents was studied in freshly isolated smooth muscle cells from rat mesenteric artery. Perforated-patch recordings showed that adenosine induced transient outward currents and an overall increase in the averaged currents at higher depolarizing potentials. The changes in current activity induced by adenosine(More)
  • D W Cheung
  • 1984
The resting membrane potential of tail arteries from spontaneously hypertensive rats (SHRs) and Wistar-Kyoto controls (WKYs) was compared. At 4-5 weeks old, the blood pressure and resting membrane potential of the SHRs was not significantly different from the WKYs. The blood pressure of 8- to 10-week-old SHRs increased significantly to 183 mmHg (1 mmHg =(More)
The role of the endothelium in the potentiating action of neuropeptide Y (NPY) to contraction induced by KCl, alpha, beta-methylene ATP (mATP), and noradrenaline (NA) was tested on rat tail arteries. Endothelium-intact and denuded ring segments and freshly isolated single smooth muscle cells were used in the study. Contraction responses to KCl and mATP were(More)
The responses of the rat saphenous vein to potassium depolarization, noradrenaline and B-HT 920 were potentiated significantly by phorbol 12,13-dibutyrate (PDBu) (10 nM). In contrast, only the contraction induced by potassium depolarization was potentiated by PDBu in the rat tail artery. The responses to noradrenaline and methoxamine were slightly(More)
The participation of presynaptic adrenoceptors and receptors mediating the postsynaptic excitatory junction potential (e.j.p.) responses in feedback regulation of neurotransmission in the guinea-pig saphenous artery was studied by electrophysiological recording of the synaptic potentials. Stimulation of perivascular nerves elicited e.j.p. and slow(More)