title: Transient receptor potential vanilloid subfamily 1 expressed in pancreatic islet beta cells modulates insulin secretion in rats.
abstract: Capsaicin-sensitive afferent neurons including transient receptor potential vanilloid subfamily 1, TRPV1, and neurohormonal peptides participate in the physiological regulation of pancreatic endocrine. However, the direct effect of capsaicin on insulin secretion remains unknown. Our present study showed that TRPV1 is expressed in islet beta cells as well as in neurons in rat pancreas, and also in rat beta cell lines, RIN and INS1. Capsaicin (10(-11)-10(-9) M) dose-dependently increased insulin secretion from RIN cells, and this effect was inhibited by either a TRPV1 inhibitor capsazepine or EDTA. Systemic capsaicin (10 mg/kg, s.c.) increased plasma insulin level 1 h after the treatment. We demonstrated for the first time that TRPV1 is functionally expressed in rat islet beta cells and plays a role in insulin secretion as a calcium channel. This study may account for the influences of capsaicin on the food intake and energy consumption as well as on the pathophysiological regulation of pancreatic endocrine.
authors.affiliation: Department of Internal Medicine, School of Medicine, Keio University, Tokyo 160-8582, Japan. yakiba@verizon.net
authors.forename: Yasutada
authors.initials: Y
authors.lastname: Akiba
authors.forename: Shinichi
authors.initials: S
authors.lastname: Kato
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Katsube
authors.forename: Masahiko
authors.initials: M
authors.lastname: Nakamura
authors.forename: Koji
authors.initials: K
authors.lastname: Takeuchi
authors.forename: Hiromasa
authors.initials: H
authors.lastname: Ishii
authors.forename: Toshifumi
authors.initials: T
authors.lastname: Hibi
mesh_terms: D000818:Animals; D002211:Capsaicin / Q000031:analogs & derivatives* / Q000494:pharmacology; D045744:Cell Line, Tumor; D017931:DNA Primers; D005727:Ganglia, Spinal / Q000166:cytology / Q000502:physiology; D005786:Gene Expression Regulation / Q000235:genetics; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007340:Insulinoma; D007473:Ion Channels; D007515:Islets of Langerhans / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D008297:Male; D010190:Pancreatic Neoplasms; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D011955:Receptors, Drug / Q000235:genetics / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D050916:TRPV Cation Channels
chemical_list: D017931:DNA Primers; D007328:Insulin; D007473:Ion Channels; D012333:RNA, Messenger; D011955:Receptors, Drug; D050916:TRPV Cation Channels; C476722:Trpv2 protein, rat; C071423:capsazepine; D002211:Capsaicin