Comparison between alpha-adrenergic- and K-opioidergic-mediated inositol (1,4,5)P3/inositol (1,3,4,5) P4 formation in adult cultured rat ventricular cardiomyocytes.
In adult cultured rat ventricular cardiac myocytes, both the alpha-adrenergic agonist phenylephrine and the selective kappa opioid receptor ligand U-50, 488H affected phosphoinositide turnover. Phenylephrine, over a time course of 10 min, caused a transient increase in Ins(1,4,5)P3 which peaked at 1 min and had returned to control at 2 min. In addition, phenylephrine produced a progressive and sustained increase in the formation of Ins (1,3,4,5)P4 which achieved a plateau after 5 min of exposure to the agonist. U-50,488H induced an increase in Ins(1,4,5)P3 which peaked at 1 min at a level significantly higher than that due to phenylephrine and was still elevated after 10 min exposure to the kappa opioid receptor agonist. In addition, U-50,488H caused a sustained increase in Ins(1,3,4,5)P4 which was comparable to that due to phenylephrine. The stimulatory effects produced by phenylephrine and U-50,488H were receptor-mediated events, since they were fully antagonized by their respective antagonists, phentolamine or Mr-1452.
Ventura
C
C
Institute of Biochemistry, University of Sassari, Italy.
Guarnieri
C
C
Stefanelli
C
C
Cirielli
C
C
Lakatta
E G
EG
Capogrossi
M C
MC
D019900:3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer; D000818:Animals; D001575:Benzomorphans / Q000494:pharmacology; D002478:Cells, Cultured; D002851:Chromatography, High Pressure Liquid; D004723:Endorphins / Q000037:antagonists & inhibitors; D006352:Heart Ventricles / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism*; D007295:Inositol Phosphates / Q000378:metabolism*; D010646:Phentolamine / Q000494:pharmacology; D010656:Phenylephrine / Q000494:pharmacology*; D011759:Pyrrolidines / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains
D001575:Benzomorphans; D004723:Endorphins; D007295:Inositol Phosphates; D011759:Pyrrolidines; C081655:inositol-1,3,4,5-tetrakisphosphate; D010656:Phenylephrine; D019900:3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer; C029552:Mr 1452; D015544:Inositol 1,4,5-Trisphosphate; D010646:Phentolamine