kappa-Opioid receptor stimulation increases intracellular free calcium in isolated rat ventricular myocytes.
The effect of two specific kappa-agonists, dynorphinA1-13 and U50,488H, on intracellular free calcium [Ca]i in isolated rat ventricular myocytes was studied. A spectrofluorimetric method using fura 2 as calcium indicator was employed. It was found that both agonists increased [Ca]i dose-dependently. The effect was attenuated by Mr 2266, a kappa-antagonist, indicating that the effect is a kappa-receptor mediated event. The effect was abolished by pretreatment with ryanodine, a drug that mobilizes calcium from the sarcoplasmic reticulum. It was, however, not affected by nifedipine, a calcium antagonist or removal of external calcium. The results indicate that the increase in [Ca]i due to kappa-opioid receptor stimulation results primarily from mobilization of calcium from an intracellular pool.
Department of Physiology, University of Hong Kong.
K K
KK
Tai
C F
CF
Bian
T M
TM
Wong
D019900:3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer; D000700:Analgesics / Q000494:pharmacology; D000818:Animals; D001575:Benzomorphans / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D004399:Dynorphins / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D005456:Fluorescent Dyes; D016257:Fura-2 / Q000031:analogs & derivatives / Q000378:metabolism; D006352:Heart Ventricles / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D009132:Muscles / Q000166:cytology / Q000187:drug effects; D009292:Narcotic Antagonists / Q000494:pharmacology; D010446:Peptide Fragments / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D011759:Pyrrolidines / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D011957:Receptors, Opioid / Q000378:metabolism*; D017473:Receptors, Opioid, kappa; D012433:Ryanodine / Q000494:pharmacology
D000700:Analgesics; D001575:Benzomorphans; D005456:Fluorescent Dyes; D009292:Narcotic Antagonists; D010446:Peptide Fragments; D011759:Pyrrolidines; D011957:Receptors, Opioid; D017473:Receptors, Opioid, kappa; C049925:fura-2-am; D012433:Ryanodine; C027247:MR 2266; D019900:3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer; C026843:dynorphin (1-13); D004399:Dynorphins; D002118:Calcium; D016257:Fura-2