[Comparing effects of U50488H, prazosin and/or propranolol on cardiac hypertrophy induced by NE in rat].
OBJECTIVE
To demonstrate the inhibitory effect of kappa-opioid receptor activation by U50488H on hypertrophy induced by NE in cultured neonatal rat cardiac myocytes and compare its effect with that of prazosin and propranolol.


METHODS
The cellular proliferation was determined with crystal violet staining. The protein content was assayed with Lowry's method. The cardiomyocytes volumes were measured by computer photograph analysis system. The protein synthesis was assayed with [3H]-lencine incorporation method.


RESULTS
(1) NE significantly induced the increase of protein content, [3H]-leucine incorporation and cell size without a concomitant increase in cell number in low serum medium. OThese responses were partially suppressed by prazosin or propranolol alone and completely abolished by both in combination. U50488H significantly inhibited the NE-induced increase of protein content, [3H]-leucine incorporation and cell size. The inhibitory effects of U50488H on NE-induced cardiac hypertrophy were greater than either prazosin or propranolol, but comparable to combination of both.


CONCLUSIONS
NE, acting via both alpha1- and beta-adrenergic pathway, stimulates myocyte hypertrophy. Stimulating kappa-opioid receptor significantly inhibits NE-induced cardiac hypertrophy, which may be related with alpha1- and beta1-adrenergic pathway.
Wang
Gui-jun
GJ
The First Affiliated Hospital, Liaoning Medical College, China.
Yao
Yu-sheng
YS
Wang
Hong-xin
HX
D019900:3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer / Q000494:pharmacology*; D058668:Adrenergic alpha-1 Receptor Antagonists / Q000494:pharmacology; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn; D006332:Cardiomegaly / Q000139:chemically induced / Q000473:pathology / Q000517:prevention & control*; D049108:Cell Enlargement / Q000187:drug effects; D002478:Cells, Cultured; D005260:Female; D008297:Male; D032383:Myocytes, Cardiac / Q000166:cytology; D009638:Norepinephrine; D011224:Prazosin / Q000494:pharmacology*; D011433:Propranolol / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017473:Receptors, Opioid, kappa / Q000819:agonists*
D058668:Adrenergic alpha-1 Receptor Antagonists; D000319:Adrenergic beta-Antagonists; D017473:Receptors, Opioid, kappa; D019900:3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer; D011433:Propranolol; D009638:Norepinephrine; D011224:Prazosin