Pharmacological characterization of a Bombyx mori alpha-adrenergic-like octopamine receptor stably expressed in a mammalian cell line.
Series of agonists and antagonists were examined for their actions on a Bombyx morialpha-adrenergic-like octopamine receptor (OAR) stably expressed in HEK-293 cells. The rank order of potency of the agonists was clonidine>naphazoline>tolazoline in Ca(2+) mobilization assays, and that of the antagonists was chlorpromazine>yohimbine. These findings suggest that the B. mori OAR is more closely related to the class-1 OAR in the intact tissue than to the other classes. N'-(4-Chloro-o-tolyl)-N-methylformamidine (DMCDM) and 2-(2,6-diethylphenylimino)imidazolidine (NC-5) elevated the intracellular calcium concentration ([Ca(2+)](i)) with EC(50)s of 92.8 microM and 15.2 nM, respectively. DMCDM and NC-5 led to increases in intracellular cAMP concentration ([cAMP](i)) with EC(50)s of 234 nM and 125 nM, respectively. The difference in DMCDM potencies between the cAMP and Ca(2+) assays might be due to "functional selectivity." The Ca(2+) and cAMP assay results for DMCDM suggest that the elevation of [cAMP](i), but not that of [Ca(2+)](i), might account for the insecticidal effect of formamidine insecticides.
Huang
Jia
J
Institute of Insect Sciences, Zhejiang University, Hangzhou, China.
Hamasaki
Tomohiro
T
Ozoe
Yoshihisa
Y
D000578:Amidines / Q000494:pharmacology*; D000818:Animals; D012831:Bombyx / Q000235:genetics / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D002460:Cell Line; D002746:Chlorpromazine / Q000494:pharmacology; D003000:Clonidine / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism*; D048289:Imidazolidines / Q000494:pharmacology*; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism; D007306:Insecticides / Q000494:pharmacology; D008322:Mammals; D009278:Naphazoline / Q000494:pharmacology; D011942:Receptors, Adrenergic, alpha / Q000235:genetics / Q000378:metabolism; D017982:Receptors, Biogenic Amine / Q000819:agonists* / Q000037:antagonists & inhibitors* / Q000378:metabolism; D014043:Tolazoline / Q000494:pharmacology; D015016:Yohimbine / Q000494:pharmacology
D000578:Amidines; D048289:Imidazolidines; D019476:Insect Proteins; D007306:Insecticides; D011942:Receptors, Adrenergic, alpha; D017982:Receptors, Biogenic Amine; C027604:norsynephrine receptor; D015016:Yohimbine; C077922:formamidine; D014043:Tolazoline; D000242:Cyclic AMP; D009278:Naphazoline; D003000:Clonidine; D002118:Calcium; D002746:Chlorpromazine