ISSN:
1432-2013
Keywords:
Ca channels
;
G-proteins
;
Hippocampus
;
Acetylcholine
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract Acetylcholine (Ach) reversibly reduces the high voltage-activated (HVA) calcium (Ca) current in hippocampal neurons. Pretreatment of the cells with pertussis toxin (PTX) abolishes the Ach effect, suggesting that PTX-sensitive GTP-binding regulatory proteins (G-proteins) are involved in the signal transduction mechanism that links Ach receptor activation to inhibition of Ca channel activity. This effect is mimicked by intracellular application of the nonhydrolyzable GTP analog GTPγS. Intracellular application of purified G-proteins restored the response to Ach in PTX-treated cells. Furthermore, Ach inhibits the Ca current independently of the presence of cyclic AMP and of the protein kinase C inhibitor H-7 and neither does the Ach effect on the Ca current seem to be correlated to a transient increase in intracellular Ca. Our results suggest that activation of the α-subunit of the PTX-sensitive G-protein could directly modulate the HVA Ca channel without involving second messenger systems.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00370874
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