Role of K+ channels in the PACAP-induced catecholamine secretion from the rat adrenal gland.
We eluciated whether K+ channels modulate adrenal catecholamine secretion induced by pituitary adenylate cyclase-activating polypeptide (PACAP) in the isolated perfused rat adrenal gland. PACAP (100 nM) increased adrenal epinephrine output. The PACAP-induced responses were enhanced by treatment with apamin (10-100 nM) in a concentration-dependent manner. In the presence of nifedipine (3 microM), apamin (1 microM) did not enhance the PACAP-induced responses. Charybdotoxin (1-100 nM) had little influence on the PACAP-induced responses. These results suggest that small-conductance Ca2+-activated K+ channels interfere with L-type voltage-dependent Ca2+ channels to counteract the PACAP-induced adrenal catecholamine secretion.
Fukushima
Yasuo
Y
Laboratory of Pharmacology, Graduate School of Pharmaceutical Sciences, Tohoku University, Aobayama, 980-8578, Sendai, Japan.
Nagayama
Takahiro
T
Hikichi
Hirohiko
H
Mizukami
Kazuhiko
K
Yoshida
Makoto
M
Suzuki-Kusaba
Mizue
M
Hisa
Hiroaki
H
Kimura
Tomohiko
T
Satoh
Susumu
S
D000311:Adrenal Glands / Q000187:drug effects* / Q000378:metabolism; D000818:Animals; D001030:Apamin / Q000494:pharmacology; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002395:Catecholamines / Q000378:metabolism*; D018999:Charybdotoxin / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004837:Epinephrine / Q000378:metabolism; D066298:In Vitro Techniques; D008297:Male; D009479:Neuropeptides / Q000494:pharmacology*; D009543:Nifedipine / Q000494:pharmacology; D009638:Norepinephrine / Q000378:metabolism; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D026902:Potassium Channel Blockers; D015221:Potassium Channels / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar
C495403:Adcyap1 protein, rat; D002121:Calcium Channel Blockers; D002395:Catecholamines; D009479:Neuropeptides; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D026902:Potassium Channel Blockers; D015221:Potassium Channels; D018999:Charybdotoxin; D001030:Apamin; D009543:Nifedipine; D009638:Norepinephrine; D004837:Epinephrine