Regulation of Intracellular Free Calcium in Neuronal Cells by Opioids
Abstract
The regulation of intracellular free calcium level by opioids was investigated in a sensory neuronal cell line, NDS-47 (neuroblastoma x dorsal root ganglion neuron hybrid cells), and in cultured mouse dorsal root ganglion (DRG) neurons. Receptor binding studies show that NDS-47 cells carry a high density of opioid 0 typereceptors. In these cells, delta agonists induced a transient increase in intracellular calcium concentration ([Ca2+]i) in a concentration-dependent fashion; among them, D-Ser2-Leu5-enkephalin-Thr (DSLET) and deltorphin-II were more effective than [DPen2,5]enkephalin (DPDPE). This effect was blocked by the nonselectiveopioid receptor antagonist, naloxone, and the o-receptor antagonist, naltrindole. The sub-type specific delta-receptor antagonists, 7-benzylidene naltrexone (BNTX; delta1), and naltriben (NTB; delta2), were used to characterize further the subtype of delta-receptors that mediated this response. NTB was more potent than BNTX in antagonizing DSLET-induced increase in [Ca2+]i. The increase in [Ca2+]i induced by DSLET was blocked by dihydropyridine-sensitive L-type calcium channel blockers, nifedipine (1 microM) or verapamil (1 microM), and was not observed in the absence of external calcium.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 19, 1995
- Accession Number
- AD1011466
Entities
People
- Tianlai Tang
Organizations
- Uniformed Services University of the Health Sciences