Yasuhisa Miyamoto

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Morphine antinociception after various administration routes was estimated by the tail-flick method in rats. The antinociceptive ED50 (AD50) values for i.c.v., i.t., i.c.v. + i.t. (4:1 dose ratio) and s.c. were 6.9 micrograms, 0.49 + 0.12 micrograms and 2.7 mg/kg, respectively. Isobolographic analysis of AD50 (except s.c.) suggested that concurrent(More)
Chemerin is a novel peptide that was identified as a natural ligand for ChemR23. As it has been reported to be involved in the regulation of immune responses and adipogenesis, chemerin may have a variety of physiological functions. Chemerin is synthesized as a precursor (prochemerin) and is proteolytically activated and inactivated in sequential steps,(More)
Histamine H3 receptors (H3Rs) are located on the presynaptic membranes and cell soma of histamine neurons, where they negatively regulate the synthesis and release of histamine. In addition, H3Rs are also located on nonhistaminergic neurons, acting as heteroreceptors to regulate the releases of other amines such as dopamine, serotonin, and norepinephrine.(More)
The effects of a mixture of three peptidase inhibitors (PIs), amastatin, captopril and phosphoramidon, on methionine-enkephalin (Met-enk)-, beta-endorphin (beta-end)-, dynorphin-(1-13) (Dyn)- and electroacupuncture (EA)-induced antinociception were compared in rats. EA was performed by passing electric pulses (3 Hz, 0.1-msec duration, for 45 min) through(More)
Two types of cDNA encoding PACAP receptors were isolated from the rat brain cDNA library by homology screening with a cDNA probe for VIP receptor. Nucleotide sequence analysis indicated that these two types of receptor mRNA were generated by alternative splicing mechanisms. These two cloned cDNAs were introduced into CHO cells respectively. Resultant(More)
Antinociceptive actions and effects of intracerebroventricular (i.c.v.) dynorphin-(1-13) (DYN) on morphine (MOR) analgesia and acute tolerance were studied in male Sprague-Dawley rats. Antinociceptive effect against hind paw pressure was produced by 30 micrograms of DYN, but not by 0.5-10 micrograms. Acetic acid writhing was inhibited dose-dependently by(More)
Met-enkephalin concentration-dependently and transiently inhibited the ileal twitch contraction and this inhibition gradually recovered with time. Bacitracin, phosphoramidon, thiorphan and captopril did not influence the twitch inhibition of met-enkephalin, but bestatin increased the twitch inhibitory potency of met-enkephalin and terminated it in a manner(More)
The effects of adrenalectomy on the pharmacokinetics and antinociceptive activity of morphine were investigated to elucidate the mechanism of adrenalectomy-induced potentiation of morphine antinociception in rats. Plasma concentrations of morphine were estimated specifically and serially in each rat by high performance liquid chromatography with an(More)
Dental preparation sometimes causes transient congestion, edema, and necrosis of the pulp. We hypothesized that nitric oxide (NO) is involved in the pathophysiological changes in pulp after preparation. The mRNA and protein expression of the inducible isoform of NO synthase (iNOS) was examined in murine pulp after dental preparation. The effects of NO on(More)
Adrenalectomy potentiated the antinociception of s.c. morphine (1.9-fold) but not that of i.c.v. morphine. After s.c. administration, the semilogarithmic plots of morphine content (plasma, brain, cerebrospinal fluid (CSF) or spinal cord) and morphine antinociception showed linearity for both sham-operated (SHAM) and adrenalectomized rats (ADX), and the(More)