ISSN:
1573-6830
Keywords:
phorbol dibutyrate
;
M current
;
muscarine
;
ganglion
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary 1. Effects of bath-applied phorbol dibutyrate (PDBu) on M currents (I M) and on the inhibition ofI M by muscarine and luteinizing hormone-releasing hormone (LHRH) were recorded in voltage-clamped bullfrog lumbar sympathetic ganglion cells. 2. PDBu (0.1–30µM) produced a slowly developing, irreversible and partial (⩽60%) inhibition ofI M. This effect was not replicated by 4-α-phorbol or by vehicle. 3. After treatment with PDBu, residualI M showed a reduced sensitivity to inhibition by muscarine or LHRH but not by Ba2+. The reduced response to muscarine appeared to result from a 10-fold shift in the concentration dependence for inhibition. 4. PDBu did not clearly reproduce the ability of muscarine to inhibit the slow, Ca-activated K currentI AHP or to increase the leak conductance at hyperpolarized potentials. The latter effect of muscarine was enhanced, rather than inhibited, by PDBu. 5. I M andI AHP were not inhibited by 1 mM dibutyryl cyclic AMP or by 20µM forskolin. 6. It is concluded that activation of protein kinase C, but not protein kinase A, partly replicates the effect of muscarine on frog sympathetic neurons.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00711303
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