Serotonin-mediated modulation of hypoxia-induced intracellular calcium responses in glomus cells isolated from rat carotid body.
In the present study, we examined serotonin (5-HT)-induced intracellular Ca(2+) ([Ca(2+)]i) responses to hypoxia in glomus cells isolated from carotid body (CB) of the rat. 5-HT did not induce any [Ca(2+)]i responses in clustered glomus cells during normoxia (21% O2), whereas, the perfusion of hypoxic solution (1% O2) induced repetitive increases in [Ca(2+)]i in the same specimens. The frequency and magnitude of hypoxia-induced [Ca(2+)]i changes observed in the glomus cells were enhanced in the presence of 5-HT, and this response was inhibited by the 5-HT2 receptor antagonist, ketanserin. Furthermore, RT-PCR analysis detected the expression of 5-HT1A, 5-HT1B, 5-HT1D, 5-HT1F, 5-HT2A, 5-HT2B, 5-HT3A, and 5-HT3B receptor mRNAs in extracts of the CB. These results suggest that 5-HT increases hypoxia-induced [Ca(2+)]i responses in glomus cells. 5-HT may elevate hypoxic responses in glomus cells in order to increase chemosensory activity of the CB.
Laboratory of Veterinary Anatomy and Cell Biology, Faculty of Agriculture, Iwate University, Morioka, Japan; Department of Basic Veterinary Science, United Graduate School of Veterinary Science, Gifu University, Gifu, Japan.
Takuya
T
Yokoyama
Laboratory of Veterinary Anatomy and Cell Biology, Faculty of Agriculture, Iwate University, Morioka, Japan; Department of Basic Veterinary Science, United Graduate School of Veterinary Science, Gifu University, Gifu, Japan.
Nobuaki
N
Nakamuta
Laboratory for Anatomy and Physiology, Department of Sport and Medical Science, Kokushikan University, Tama, Japan.
Tatsumi
T
Kusakabe
Laboratory of Veterinary Anatomy and Cell Biology, Faculty of Agriculture, Iwate University, Morioka, Japan; Department of Basic Veterinary Science, United Graduate School of Veterinary Science, Gifu University, Gifu, Japan. Electronic address: yyoshio@iwate-u.ac.jp.
Yoshio
Y
Yamamoto
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002344:Carotid Body / Q000166:cytology / Q000378:metabolism*; D015687:Cell Hypoxia; D042541:Intracellular Space / Q000378:metabolism*; D007650:Ketanserin / Q000494:pharmacology; D008297:Male; D012333:RNA, Messenger / Q000378:metabolism; D017208:Rats, Wistar; D011985:Receptors, Serotonin / Q000235:genetics / Q000378:metabolism; D012701:Serotonin / Q000378:metabolism* / Q000494:pharmacology; D012702:Serotonin Antagonists / Q000494:pharmacology
D012333:RNA, Messenger; D011985:Receptors, Serotonin; D012702:Serotonin Antagonists; D012701:Serotonin; D007650:Ketanserin; D002118:Calcium
Carotid body; Glomus cells; Hypoxia; Serotonin