ISSN:
1471-4159
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Medicine
Notes:
: Acute treatment of rat spinal cord-dorsal root ganglion cocultured neurons with 12-O-tetradecanoylphorbol 13-acetate (TPA), a known activator of protein kinase C, inhibited the dihydropyridinc-sensitive voltage-dependent 45Ca2+ influx measured in these cells (IC50 of⋍100 nM, 66% inhibition at 1 νM TPA). However, prolonged preincubation (24 h) of the cells with 100 nM TPA followed by extensive washing completely abolished, i.e., desensitized, the capacity of a second application of TPA to inhibit the activity of the voltage-dependent Ca2+ channels. Moreover, this treatment also abolished the inhibition of Ca2+ influx produced by k-opiate as well as by α2-adrenergic and muscarinic receptor agonists. Substantial desensitization was already observed following a 1-h pretreatment with 100 nMTPA. In contrast to TPA, an inactive phorbol ester (4β-phorbol 13-acetate) did not affect the inhibition of the voltage-dependent Ca2+ influx by these receptor agonists. These results suggest that protein kinase C may have a role in the modulation of Ca2+channels by k-opiate, α2-adrenetgic, and muscarinic receptor agonists.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1471-4159.1991.tb06384.x
