Publications by authors named "Takio Kitazawa"

Article Synopsis
  • The Concise Guide to PHARMACOLOGY 2023/24 offers a summarized overview of approximately 1800 drug targets and around 6000 interactions with 3900 ligands, mostly in a tabular format.
  • It focuses on selective pharmacology and includes links to an open access knowledgebase for more detailed drug information.
  • The guide divides drug targets into six major categories, providing essential summaries and guidance based on the latest pharmacological data available as of mid-2023, while serving as an official resource by the International Union of Basic and Clinical Pharmacology.
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  • The study investigates the effects of rat ghrelin and motilin on muscle contractions in the rabbit duodenum, particularly focusing on ghrelin's role, which has been previously linked to GI motility in other animals.
  • Results show that rat ghrelin did not influence the contractile activity of the duodenum, as its receptor mRNA was found to have low expression in this region compared to other GI areas like the esophagus and stomach.
  • Conversely, motilin successfully induced muscle contractions, suggesting that while motilin is an important player in GI motility, ghrelin does not regulate contractions in the rabbit duodenum due to a lack of its receptors.
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Sit-to-stand and stand-to-sit motions are basic motions for daily animal life, and these motions are used as therapeutic exercises for dogs with functional impairments. The sit-to-stand motion is divided into several phases for kinesiological assessment in human rehabilitation and physical therapy. However, these motions in dogs have not been characterized in detail.

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  • - The study investigated how newt motilin affects the contractility of the GI tract in Japanese fire belly newts to determine its role in GI motility for urodele amphibians.
  • - It compared the contractile responses of motilins from seven vertebrate species in GI tissues from rabbits, chickens, and newts, revealing species-specific actions and effectiveness.
  • - Results showed that newt motilin strongly induces contractions in the newt's stomach but is ineffective in the intestinal sections and highlights that motilin’s impact varies widely between species due to differences in amino acid sequences.
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The red-crowned crane Grus japonensis in Hokkaido, Japan forms a closed population as a residence that is independent of the mainland population. Based on observations of a limited number of individuals as well as cranes in captivity, red-crowned cranes are omnivores and eat fish, worms, insects and plants in their own territories except in winter, when they are fed with dent corn that is supplied in eastern Hokkaido. DNA metabarcoding based on high throughput sequencing was carried out using universal primer sets for cytochrome oxidase subunit I gene.

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Article Synopsis
  • The Concise Guide to Pharmacology 2021/22 offers a streamlined overview of nearly 1900 human drug targets, focusing on selective pharmacology and organized mainly in tables for quick reference.
  • The guide serves as a reliable, citable resource that distills extensive online content while ensuring it reflects the status as of mid-2021, distinct from ongoing database updates.
  • Key pharmacological targets include G protein-coupled receptors, ion channels, and enzymes, with official nomenclature and references provided to assist further research and understanding.
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  • Pheasant motilin, identified as a 22-amino acid peptide, was studied for its distribution and effects in the gastrointestinal (GI) tract, showing a high presence in the small intestine and limited expression in other organs.
  • The contraction studies revealed that pheasant motilin induces significant muscle contractions in the small intestine but has varying effects in other regions like the proventriculus, where its action is influenced by cholinergic nerves.
  • The findings suggest that pheasant motilin plays a crucial role in regulating small intestinal motility in birds, and its receptor characteristics differ from those in mammals, indicating a unique functionality in avian species.
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Motilin, produced in endocrine cells in the mucosa of the upper intestine, is an important regulator of gastrointestinal (GI) motility and mediates the phase III of interdigestive migrating motor complex (MMC) in the stomach of humans, dogs and house musk shrews through the specific motilin receptor (MLN-R). Motilin-induced MMC contributes to the maintenance of normal GI functions and transmits a hunger signal from the stomach to the brain. Motilin has been identified in various mammals, but the physiological roles of motilin in regulating GI motility in these mammals are well not understood due to inconsistencies between studies conducted on different species using a range of experimental conditions.

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We reported the involvement of oxidative stress and prostaglandins including thromboxane and prostacyclin in pre-cardiac edema (early edema) caused by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). While the involvement of oxidative stress in TCDD-induced toxicity has been frequently reported, the mechanism of its action is still unclear. In the present study, oxidative stress inducers including paraquat, hydrogen peroxide (HO) and rotenone augmented early edema (edema) induced by a low concentration of TCDD (0.

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Parasympathetic signalling via muscarinic acetylcholine receptors (mAChRs) regulates gastrointestinal smooth muscle function. In most instances, the mAChR population in smooth muscle consists mainly of M and M subtypes in a roughly 80% to 20% mixture. Stimulation of these mAChRs triggers a complex array of biochemical and electrical events in the cell via associated G proteins, leading to smooth muscle contraction and facilitating gastrointestinal motility.

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Zebrafish are used widely in biomedical, toxicological, and developmental research, but information on their xenobiotic metabolism is limited. Here, we characterized the expression of 14 xenobiotic cytochrome P450 (CYP) subtypes in whole embryos and larvae of zebrafish (4 to 144 h post-fertilization (hpf)) and the metabolic activities of several representative human CYP substrates. The 14 CYPs showed various changes in expression patterns during development.

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In humans, walking analysis based on the gait phase classification has been used for interpretation of functional roles of different movements occurring at individual joints, and it is useful for establishing a rehabilitation plan. However, there have been few reports on canine gait phase classification, and this is one of the reasons for preventing progress in canine rehabilitation. In this study, we determined phases of the canine gait cycle (GC) on the basis of the phase classification for human gait.

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Ghrelin (GHRL) and motilin (MLN), gut peptides isolated from the mucosa of the stomach and duodenum, respectively, stimulate gastrointestinal (GI) motility in mammals and birds. However, the functions of MLN and GHRL in amphibian GI tracts have not been examined in detail. To clarify the regulation of GI motility by the two peptides, the effects of human MLN and rat GHRL on contractility of isolated GI strips from three species of frogs, the black-spotted pond frog (pond frog; Pelophylax nigromaculata), bullfrog (Lithobates catesbeiana) and Western clawed frog (Xenopus; Xenopus tropicalis), were examined in in vitro experiments.

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2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) has adverse effects on the development and function of the heart in zebrafish eleutheroembryos (embryos and larvae). We previously reported that TCDD reduced blood flow in the mesencephalic vein of zebrafish eleutheroembryos long before inducing pericardial edema. In the present study, we compared early edema (pre-cardiac edema), reduction of deduced cardiac output and reduction of blood flow in the dorsal aorta and cardinal vein caused by TCDD.

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Motilin and ghrelin were identified in the pheasant by molecular cloning, and the actions of both peptides on the contractility of gastrointestinal (GI) strips were examined in vitro. Molecular cloning indicated that the deduced amino acid sequences of the pheasant motilin and ghrelin were a 22-amino acid peptide, FVPFFTQSDIQKMQEKERIKGQ, and a 26-amino acid peptide, GSSFLSPAYKNIQQQKDTRKPTGRLH, respectively. In in vitro studies using pheasant GI strips, chicken motilin caused contraction of the proventriculus and small intestine, whereas the crop and colon were insensitive.

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The energy balance of vertebrates is regulated by the difference in energy input and energy expenditure. Generally, most vertebrates obtain their energy from nutrients of foods through the gastrointestinal (GI) tract. Therefore, food intake and following food digestion, including motility of the GI tract, secretion and absorption, are crucial physiological events for energy homeostasis.

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Knowledge of genetic polymorphisms of cytochrome P450 (CYP), the most important xenobiotic metabolizing enzyme, is very limited in cats. Preliminarily, we investigated genetic polymorphisms in CYP2A13, one of the major CYP isoforms in the liver and lung. Four synonymous and three non-synonymous polymorphic variants were identified in feline CYP2A13 in domestic cats in Japan, without an obvious major type.

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Knowledge of genetic polymorphisms of metabolizing enzymes of medical drugs and xenobiotics including cytochrome P450 (CYP) is very limited in cats. We investigated polymorphisms in CYP1A2, one of the major CYP isoforms in the feline liver. Wild-type and three non-synonymous polymorphic variants, but no synonymous variant, were identified in feline CYP1A2 in 50 alleles of domestic cats in Japan.

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Increasing use of zebrafish in biomedical, toxicological and developmental studies requires explicit knowledge of cytochrome P450 (CYP), given the central role of CYP in oxidative biotransformation of xenobiotics and many regulatory molecules. A full complement of CYP genes in zebrafish and their transcript expression during early development have already been examined. Here we established a comprehensive picture of CYP gene expression in the adult zebrafish liver using a RNA-seq technique.

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Knowledge on genetic polymorphisms of metabolising enzymes including cytochrome P450 (CYP) is very limited in cats. We investigated polymorphisms in CYP3A131, one of the major CYP isoforms in the feline liver and small intestine. Eight non-synonymous variants and one synonymous variant of feline CYP3A131 were identified in 29 cats.

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Motilin (MLN), a 22-amino-acid peptide hormone, is generally present in the mucosa of the upper gastrointestinal (GI) tract, mainly the duodenum of mammals, and it regulates GI motility, especially that related to interdigestive migrating contraction. However, MLN and its receptor are absent in mice and rats, and MLN does not cause any mechanical responses in the rat and mouse GI tracts. The guinea-pig is also a rodent, but expression of the MLN gene in the guinea-pig has been reported.

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Modulation of cardiac contractility by α-adrenoceptor is well known in several mammals. Mice are useful experimental animals, but α-adrenoceptor-mediated responses have been examined only in the ventricles. To determine function of α-adrenoceptors in the atrium, effects of α-adrenoceptor agonists on spontaneous contraction and electrical-field stimulation (EFS)-induced contraction were examined.

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Contamination with polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in the environment is a major concern due to their persistent bioaccumulative toxicity that can disturb neurobehavioral functions including movements. Recently, it was reported that some PBDE including BDE-47 stimulates locomotor activities of zebrafish embryos by unknown mechanism. In this study, motor movements of the zebrafish embryo were used as a model system to evaluate the neuronal toxicity of a non-coplanar PCB-dominant mixture (Aroclor 1254) and BDE-47.

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The hooded crane is designated as an endangered species. The cranes breed primarily in wetlands in southeast Russia and China in summer. Most of the hooded crane population winters in the Izumi plain in Japan.

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1. Compared to information for herbivores and omnivores, knowledge on xenobiotic metabolism in carnivores is limited. The cytochrome P450 2C (CYP2C) subfamily is recognized as one of the most important CYP groups in human and dog.

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