Kazuhiko Shibata

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An opiate antagonist was found to induce motivational withdrawal signs 24 h or even up to 48 h after a single dose of morphine in rats. The present study was undertaken to determine whether such a withdrawal state would modify the neuronal activity in the brain. A conditioned place aversion was established following a one-trial paradigm in rats undergoing a(More)
The effectiveness of two inducible nitric oxide synthase (iNOS) inhibitors on allergic airway inflammation was investigated under different administration schedules. Rats sensitized to ovalbumin (OVA) were exposed to OVA for 3 consecutive days. Both iNOS inhibitors showed markedly different effects between two pretreatment schedules: pretreatment before(More)
Ghrelin, an endogenous ligand for the growth hormone secretagogues, was originally isolated from rat stomach. It stimulates the release of growth hormone from primary pituitary cell cultures. We investigated the plasma concentration of ghrelin peptide in 16 nonpregnant women, 18 normal pregnant women, 20 patients with pregnancy-induced hypertension, and 10(More)
The neurobiological mechanism underlying the negative motivational component of withdrawal from acute opiate dependence is far from understood. Our objectives were to determine whether the glutamatergic system is involved in the motivational component of morphine withdrawal in acutely dependent rats and such an involvement is associated with dopaminergic(More)
Recently, it was demonstrated that the priming stimulation effect (PSE) of intracranial self-stimulation (ICSS) with the runway method can be used as a model system to study the motivation that contributes to specific behaviors. It was postulated that these behaviors could be used to compare the effects of various drugs on the mechanism of motivation. In(More)
In the present study, we investigated the effect of adrenocorticotropic hormone (ACTH) on the immobilization of rats in the forced swim test after the administration of selegiline, a selective and irreversible monoamine oxidase (MAO)-B inhibitor. Single and repeated administration of selegiline significantly decreased the duration of immobility in normal(More)
Nicotine has been reported to normalize deficits in auditory sensory gating in the cases of schizophrenia, suggesting an involvement of nicotinic acetylcholine receptors in attentional abnormalities. However, the mechanism remains unclear. The present study investigated the effects of nicotine on the disruption of prepulse inhibition (PPI) of the acoustic(More)
Acute physical dependence refers to the withdrawal syndrome precipitated by an opioid antagonist administered several hours after either a single dose or a short-term infusion of an opioid agonist. We examined the mechanism of nicotine-induced attenuation of naloxone-precipitated withdrawal syndrome when used to produce an aversive motivational state in a(More)
Conditioned reinforcement is hypothesized to be critically involved in drug addiction as a factor contributing to compulsive drug use and relapse. The present study focused on the neurobiology involved in the acquisition and expression of conditioned reinforcing effects of morphine withdrawal employing a conditioned place aversion (CPA) paradigm in(More)