Yohtaro Sakakibara

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Delayed treatment with nicotinamide (NAm) protects male rats against cerebral ischemia. Since the preponderant use of male animals in stroke research may produce results not applicable to female stroke patients due to gender-related differences, we examined whether delayed NAm treatment could protect female rats against focal cerebral ischemia using a model(More)
Although fast sodium current (INa) plays a major role in the generation and conduction of the cardiac impulse, the electrophysiological characteristics of INa in isolated human ventricular myocytes have not yet been fully described. We characterized the human ventricular INa of enzymatically isolated myocytes using whole cell voltage-clamp techniques. Sixty(More)
Patch-clamp recording techniques have permitted measurement of the fast Na+ current (INa) in isolated cardiac cells from a number of species in recent years. However, there is still only very little information concerning human cardiac INa. The purpose of this study was to describe the kinetics of INa in normal-appearing, Ca(2+)-tolerant, enzymatically(More)
In the rabbit iris sphincter muscle, electrical transmural stimulation produced fast and slow components of contraction which were markedly attenuated by tetrodotoxin. The fast component was augmented by physostigmine and was abolished by atropine, while the slow component was little affected. Adrenergic and ganglionic blocking agents did not inhibit the(More)
The effects of optically pure d-nicotine were investigated as compared with those of the l-isomer. d-Nicotine showed qualitatively the same effects as the l-isomer in the ganglionic or neuromuscular sites and the relative potency of the d-isomer was approximately 0.06 in the case of rat blood pressure (elevation), approximately 0.2 in the cat superior(More)
The transmission mechanism of sympathetic neuroeffector was studied in the isolated dog basilar artery. Electrical transmural stimulation produced an initial contractile response which was followed by a transient relaxation or a late contraction, or both relaxation and contraction. These arteries showed a marked uptake of [3H]norepinephrine ([3H]NE) or(More)
BACKGROUND AND PURPOSE We have previously shown that nicotinamide (NAm) acutely reduces brain infarction induced by permanent middle cerebral artery occlusion (MCAo) in rats. In this study, we investigate whether NAm may protect against ischemia/reperfusion injury by improving sensory and motor behavior as well as brain infarction volumes in a model of(More)
Effects of guanabenz, a hypotensive agent, on the adrenergic mechanism were studied in isolated rabbit thoracic aorta and pulmonary artery and findings were compared with data obtained with clonidine and guanethidine. Guanabenz in concentrations higher than 10(-6) M produced weak contractions which were attenuated by phentolamine or yohimbine. Such(More)
Since hypertension and/or hyperglycemia are risk factors for stroke, we examined whether the putative neuroprotectant, nicotinamide (NAm), could protect spontaneously hypertensive rats (SHR) or diabetic Fischer 344 rats against focal cerebral ischemia using a model of permanent middle cerebral artery occlusion (MCAo). Intravenous NAm given 2 h after MCAo(More)