Hiroyuki Ohkawa

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The electrical and mechanical activity of the smooth muscle of the guinea-pig prostate gland was studied. The electrical activity of the cells was recorded intracellularly. The resting membrane potential was about -50-60 mV. The majority of cells was electrically quiescent but some cells generated action potentials spontaneously in the normal solution. The(More)
Spontaneous excitatory junction potentials (e.j.p.s) from the circular smooth muscle cells of the guinea-pig seminal vesicle were recorded intracellularly. Their mean amplitude and frequency were 2.6 mV and 26.6/min, respectively. Occasionally large e.j.p.s were recorded. The circular smooth muscle of the tissue generated the action potential spontaneously,(More)
Effects of gastrointestinal hormones on electrical and mechanical activity of smooth muscle of cat stomach were studied. Spontaneous electrical activity of the antrum preparation consisted of slow waves with superimposed spike-like potentials. Phasic contractions occurred synchronously with the electrical activity. Pentagastrin, tetragastrin, pancreozymin(More)
Hematopoietic cellular interaction was investigated in a coculture of the human clonal marrow stromal line, KM-102, and the myeloid leuke mia cell line, HL-60. In the coculture, a large number of HL-60 cells remained in the supernatant but some of them became firmly attached to KM-102 cells. The attached HL-60 cells showed Unie positive reaction in the NBT(More)
The spontaneous single spikes in the myenteric plexus of the guinea-pig duodenum were recorded extracellularly. The myenteric plexus neurones in the cardiac region of the stomach also exhibited the spontaneous single spike activity. The frequency of these spikes was at low level. By the treatment with a high Mg and Ca-free Krebs solution, the single spikes(More)
Effects of calcitonin gene-related peptide (CGRP) on the spontaneous and evoked contractions in the duodenal and ileal preparations, the spontaneous action potentials and the non-adrenergic non-cholinergic inhibitory potentials (NANC i.p.s) in the longitudinal smooth muscle cells of the guinea-pig duodenum and ileum were examined. Preparations were(More)
Cholinergic modulation and effects of dynorphin on the non-adrenergic non-cholinergic inhibitory potentials (NANC i.p.s) in the longitudinal smooth muscle cells of the guinea-pig duodenum were studied intracellularly. Atropine (1.4 X 10(-7)-1.4 X 10(-5) M) and scopolamine (3.3 X 10(-8)-3.3 X 10(-7) M) increased the amplitude of the evoked i.p.s while(More)
The evoked inhibitory potentials (i.p.s) in the longitudinal smooth muscle cells of the guinea-pig duodenum were recorded intracellularly. The i.p.s were not blocked by adrenergic blocking agents, guanethidine (10(-6) g/ml), propranolol (10(-6) g/ml) and phentolamine (10(-6) g/ml), and atropine (10(-6) g/ml). Tetrodotoxin (10(-7)-10(-6) g/ml) abolished the(More)
Non-adrenergic inhibitory potentials (i.p.'s) were recorded from the smooth muscle cells of the guinea-pig duodenum following field stimulation. ATP, ADP and AMP increased the membrane potential of the cell and decreased the amplitude and the rate of hyperpolarization of the i.p. The amplitudes of the maximum hyperpolarization due to a repeated stimulation(More)