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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. Intracellular electrodes were used to compare the electrical activity of smooth muscle cells from the longitudinal and circular layers of the rabbit duodenum and their responses to stimulation of the intramural nerves. 2. The longitudinal muscle cells had an average membrane potential of 52 mV when measured between slow waves. Spontaneous action(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)
Transient local releases of Ca(2+) from the sarcoplasmic reticulum activate nearby Ca(2+)-activated K(+) channels to produce spontaneous transient outward current (STOC) in smooth muscle cells. We examined if cADP-ribose, an endogenous mediator of Ca(2+) release channels of the sarcoplasmic reticulum, could modify STOC activity. In freshly isolated rat tail(More)
1. The tunica media of the proximal segments of the pulmonary vein is made up of cardiac muscle cells. The electrical activity of this cardiac portion of the pulmonary vein was studied with intracellular micro-electrodes in isolated preparations. 2. All-or-none action potentials were recorded in all cardiac muscle cells in response to electrical(More)
Neonatal sympathectomy of spontaneously hypertensive rats (SHR) and control Wistar-Kyoto rats (WKY) was performed by a combined treatment with antiserum to nerve growth factor and guanethidine during the first 4 weeks after birth. The development of hypertension was completely prevented in the treated SHR: at 28 to 30 weeks of age, systolic blood pressure(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)
Acetylcholine (ACh) induced hyperpolarization and relaxation in rat mesenteric arteries contracted with norepinephrine, as indicated from studies with simultaneous microelectrode and tension recordings. We tested whether the hyperpolarization to ACh was modified by induction and depletion of cytochrome P450 enzymes. Enzyme induction by treating the animals(More)
Acetylcholine (ACh) induces endothelium-dependent hyperpolarization in the rat mesenteric artery in the presence of the nitric oxide synthase inhibitor N omega-nitro-L-arginine. We have now studied the effects of K(+)-channel blockers on the hyperpolarization responses to ACh in resting and norepinephrine-contracted rat mesenteric arteries. We also measured(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)