title: 5-HT7 Receptors Are Not Involved in Neuropeptide Release in Primary Cultured Rat Trigeminal Ganglion Neurons.
abstract: Migraine is a common but complex neurological disorder. Its precise mechanisms are not fully understood. Increasing indirect evidence indicates that 5-HT7 receptors may be involved; however, their role remains unknown. Our previous in vivo study showed that selective blockade of 5-HT7 receptors caused decreased serum levels of calcitonin gene-related peptide (CGRP) in the external jugular vein following electrical stimulation of the trigeminal ganglion (TG) in an animal model of migraine. In the present study, we used an in vitro model of cultured TG cells to further investigate whether 5-HT7 receptors are directly responsible for the release of CGRP and substance P from TG neurons. We stimulated rat primary cultured TG neurons with capsaicin or potassium chloride (KCl) to mimic neurogenic inflammation, resulting in release of CGRP and substance P. 5-HT7 receptors were abundantly expressed in TG neurons. Greater than 93 % of 5-HT7 receptor-positive neurons co-expressed CGRP and 56 % co-expressed substance P. Both the capsaicin- and KCl-induced release of CGRP and substance P were unaffected by pretreatment of cultured TG cells with the selective 5-HT7 receptor agonist AS19 and antagonist SB269970. This study demonstrates for the first time that 5-HT7 receptors are abundantly co-expressed with CGRP and substance P in rat primary TG neurons and suggests that they are not responsible for the release of CGRP and substance P from cultured TG neurons evoked by capsaicin or KCl.
authors.affiliation: Department of Neurology, Guangzhou First People's Hospital, Affiliated to Guangzhou Medical University, No. 1 Panfu Road, Guangzhou, 510180, China.
authors.forename: Xiaojuan
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Neurology, Guangzhou First People's Hospital, Affiliated to Guangzhou Medical University, No. 1 Panfu Road, Guangzhou, 510180, China.
authors.forename: Rong
authors.initials: R
authors.lastname: Hu
authors.affiliation: Department of Clinical Laboratory, The First Affiliated Hospital, Sun Yat-sen University, No. 58 Zhongshan 2nd Road, Guangzhou, 510080, China.
authors.forename: Jianbo
authors.initials: J
authors.lastname: Liang
authors.affiliation: Department of Neurology, Guangzhou First People's Hospital, Affiliated to Guangzhou Medical University, No. 1 Panfu Road, Guangzhou, 510180, China.
authors.forename: Ze
authors.initials: Z
authors.lastname: Li
authors.affiliation: Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Institute of Neurosciences and the Second Affiliated Hospital of Guangzhou Medical University, No. 250 Changgang Dong Road, Guangzhou, 510260, China.
authors.forename: Weiwen
authors.initials: W
authors.lastname: Sun
authors.affiliation: Department of Neurology, Guangzhou First People's Hospital, Affiliated to Guangzhou Medical University, No. 1 Panfu Road, Guangzhou, 510180, China. panxiaoping@gzhmu.edu.cn.
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Pan
mesh_terms: D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000235:genetics / Q000378:metabolism*; D002211:Capsaicin / Q000494:pharmacology; D002478:Cells, Cultured; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011985:Receptors, Serotonin / Q000235:genetics / Q000378:metabolism*; D012702:Serotonin Antagonists / Q000494:pharmacology; D017366:Serotonin Receptor Agonists / Q000494:pharmacology; D013373:Substance P / Q000235:genetics / Q000378:metabolism*; D012668:Trigeminal Ganglion / Q000166:cytology / Q000378:metabolism*
chemical_list: D011985:Receptors, Serotonin; D012702:Serotonin Antagonists; D017366:Serotonin Receptor Agonists; C104425:serotonin 7 receptor; D013373:Substance P; D011189:Potassium Chloride; D015740:Calcitonin Gene-Related Peptide; D002211:Capsaicin
keywords: 5-HT7 receptor; CGRP; Substance P; Trigeminal ganglion