Voltage-gated Ca2+ channel mRNAs and T-type Ca2+ currents in rat gonadotropin-releasing hormone neurons.
Gonadotropin-releasing hormone (GnRH) neurons play a pivotal role in the neuroendocrine regulation of reproduction. We have previously reported that rat GnRH neurons exhibit voltage-gated Ca(2+) currents. In this study, oligo-cell RT-PCR was carried out to identify subtypes of the alpha(1) subunit of voltage-gated Ca(2+) channels in adult rat GnRH neurons. GnRH neurons expressed mRNAs for all five types of voltage-gated Ca(2+) channels. For T-type Ca(2+) channels, alpha(1H) was dominantly expressed in GnRH neurons. Electrophysiological analysis in acute slice preparations revealed that GnRH neurons from adult rats exhibited T-type Ca(2+) currents with fast inactivation kinetics (~20 ms at -30 mV) and a time constant of recovery from inactivation of ~0.6 s. These results indicate that rat GnRH neurons express subtypes of the alpha(1) subunit for all five types of voltage-gated Ca(2+) channel, and that alpha(1H) was the dominant subtype in T-type Ca(2+) channels.
Tanaka
Nobuyuki
N
Department of Physiology, Nippon Medical School, Sendagi 1, Bunkyo, Tokyo, Japan.
Ishii
Hirotaka
H
Yin
Chengzhu
C
Koyama
Makiko
M
Sakuma
Yasuo
Y
Kato
Masakatsu
M
D000818:Animals; D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism* / Q000494:pharmacology; D009474:Neurons / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D055647:Rats, Transgenic; D020133:Reverse Transcriptase Polymerase Chain Reaction
D012333:RNA, Messenger; D007987:Gonadotropin-Releasing Hormone; D002118:Calcium