The role of area postrema neurons expressing H-channels in the induction mechanism of nausea and vomiting.
The area postrema is one of the circumventricular organs, lacks a blood-brain barrier, and is well known as the chemoreceptor trigger zone for emesis. Area postrema neurons are sensitive to emetic chemical substances carried in the blood plasma. Our previous study demonstrated the presence of 3 types of neurons characterized by different ion channels expressed in each cell type, but the type or types of area postrema neurons involved in the induction of nausea and/or emesis have remained unclear. To clarify the role of the most populous cells, which express the hyperpolarization-activated cation channel (H-channel), in induction of nausea and/or emesis, we investigated the effects of ZD7288 (an H-channel inhibitor) on apomorphine-induced conditioned taste aversion (CTA) to saccharin and c-Fos expression in the area postrema. We found that ZD7288 inhibited the acquisition of CTA and reduced apomorphine-induced c-Fos expression in the area postrema, indicating the involvement of the cells expressing H-channels in the induction of nausea and/or emesis. Finally, we discuss the role of cells expressing H-channels in the mechanism of nausea and/or vomiting.
Department of Oral and Maxillofacial Surgery, Graduate School of Dental Medicine, Hokkaido University, Kita 13, Nishi 7, Kita-ku, Sapporo 060-8586, Japan. shimpo@den.hokudai.ac.jp
Keisuke
K
Shinpo
Yoshiyuki
Y
Hirai
Hitoshi
H
Maezawa
Yasunori
Y
Totsuka
Makoto
M
Funahashi
D000704:Analysis of Variance; D000818:Animals; D001058:Apomorphine / Q000009:adverse effects; D031608:Area Postrema / Q000473:pathology*; D001362:Avoidance Learning / Q000187:drug effects; D003214:Conditioning, Classical / Q000502:physiology; D054815:Cyclic Nucleotide-Gated Cation Channels / Q000378:metabolism*; D018491:Dopamine Agonists / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004327:Drinking Behavior / Q000187:drug effects; D005247:Feeding Behavior / Q000187:drug effects; D005518:Food Preferences / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology; D064428:Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels; D009325:Nausea / Q000139:chemically induced / Q000473:pathology*; D009474:Neurons / Q000378:metabolism*; D015221:Potassium Channels / Q000378:metabolism*; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D011743:Pyrimidines / Q000009:adverse effects; D051381:Rats; D017208:Rats, Wistar; D013649:Taste / Q000187:drug effects / Q000502:physiology; D014839:Vomiting / Q000139:chemically induced / Q000473:pathology*
D054815:Cyclic Nucleotide-Gated Cation Channels; D018491:Dopamine Agonists; D064428:Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels; D015221:Potassium Channels; D016760:Proto-Oncogene Proteins c-fos; D011743:Pyrimidines; C082246:ICI D2788; D001058:Apomorphine