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Responses of the silkworm tyramine receptor to 2‐phenylethylamines and 5‐phenyloxazoles
Author(s) -
Ohta Hiroto,
Khan Md. Anwar Arfien,
Nagai Idumi,
Umemoto Natsuko,
Hamasaki Tomohiro,
Ozoe Yoshihisa
Publication year - 2005
Publication title -
archives of insect biochemistry and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.576
H-Index - 66
eISSN - 1520-6327
pISSN - 0739-4462
DOI - 10.1002/arch.20066
Subject(s) - forskolin , receptor , ethylamine , tyramine , agonist , biology , receptor antagonist , biochemistry , medicine , endocrinology , microbiology and biotechnology , antagonist , chemistry , organic chemistry
Tyramine (TA), a biogenic amine, attenuates intracellular cAMP production by acting on its receptor in insects. Several non‐biogenic amines were examined for their actions on native and heterologously expressed silkworm TA receptors. 5‐(4‐Hydroxyphenyl)oxazole, which showed an attenuating effect on cAMP production in silkworm‐head membranes, did not attenuate forskolin‐stimulated cAMP production in HEK‐293 cells expressing the silkworm TA receptor, although the compound bound to the cloned receptor. 2‐Phenylethylamines (2‐PEAs), which showed positive and negative effects on cAMP production in silkworm‐head membranes, inhibited [ 3 H]TA binding to the cloned TA receptor. 2‐Chloro‐2‐(4‐chlorophenyl)ethylamine was the most potent inhibitor of [ 3 H]TA binding among the 2‐PEAs tested, with an IC 50 of 30.4 nM. This compound acted as an antagonist and abolished TA‐attenuation of forskolin‐stimulated cAMP production in the cloned TA receptor. The discrepancy in the effects of the non‐biogenic amines on the native and cloned TA receptors remains to be further examined. A newly synthesized 2‐PEA, 2‐chloro‐2‐(4‐hydroxyphenyl)ethylamine, attenuated forskolin‐stimulated cAMP production in the cloned TA receptor, indicating that the para ‐hydroxy group is important for the agonist action. Arch. Insect Biochem. Physiol. 59:150–160, 2005. © 2005 Wiley‐Liss, Inc.