Influence of stimulation on Ca2+ recruitment triggering [H-3]acetylcholine release from the rat motor-nerve endings

• Type: Article in International Scientific Journal
• Date: 2000

Authors

Paulo Correia de Sá (Author) ICBAS; Timoteo, MA (Author) Other; Ribeiro, JA (Author) Other

Journal

Title: European Journal of Pharmacology

Vol. 406

Pages: 355-362

ISSN: 0014-2999

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 16 Citations

Scopus - 18 Citations

Other information

Authenticus ID: P-000-YQA

DOI: 10.1016/s0014-2999(00)00686-5

Abstract (EN): The influence of rat phrenic nerve stimulation frequency (5-50 Hz) and of pulse duration (0.04-1 ms) on Ca2+ mobilization triggering [H-3]acetylcholine release was investigated. The P-type voltage-dependent Ca2+ channel(VDCC) blocker, omega -agatoxin IVA (100 nM), decreased [H-3]acetylcholine release evoked by pulses of 0.04-ms duration delivered at 5 Hz frequency. When the stimulus pulse duration was increased to 1 ms (5 Hz frequency) or the stimulation frequency to 50 Hz (0.04-ms duration), inhibition of [H-3]acetylcholine release became evident after blockade of L-type VDCC, with nifedipine (1 muM), and/or depletion of thapsigargin-sensitive internal stores. The inhibitory effect of thapsigargin (2 muM) was still observed in Ca2+-free medium. Neither omega -conotoxin GVIA (1 muM) nor omega -conotoxin MWC (150 nM) modified neurotransmitter release. The results suggest that, depending on the stimulus paradigm, both internal (thapsigargin-sensitive) and external (either P- or L-type channels) Ca2+ pools can be mobilized to promote acetylcholine release from motor nerve terminals.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 8