Ca2+ -dependent and Ca2+ -independent somatic release from trigeminal neurons.
J Cell Physiol
; 234(7): 10977-10989, 2019 07.
Article
em En
| MEDLINE
| ID: mdl-30536400
ABSTRACT
Besides the nerve endings, the soma of trigeminal neurons also respond to membrane depolarizations with the release of neurotransmitters and neuromodulators in the extracellular space within the ganglion, a process potentially important for the cross-communication between neighboring sensory neurons. In this study, we addressed the dependence of somatic release on Ca2+ influx in trigeminal neurons and the involvement of the different types of voltage-gated Ca2+ (Cav) channels in the process. Similar to the closely related dorsal root ganglion neurons, we found two kinetically distinct components of somatic release, a faster component stimulated by voltage but independent of the Ca2+ influx, and a slower component triggered by Ca2+ influx. The Ca2+ -dependent component was inhibited 80% by ω-conotoxin-MVIIC, an inhibitor of both N- and P/Q-type Cav channels, and 55% by the P/Q-type selective inhibitor ω-agatoxin-IVA. The selective L-type Ca2+ channel inhibitor nimodipine was instead without effect. These results suggest a major involvement of N- and P/Q-, but not L-type Cav channels in the somatic release of trigeminal neurons. Thus antinociceptive Cav channel antagonists acting on the N- and P/Q-type channels may exert their function by also modulating the somatic release and cross-communication between sensory neurons.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Nervo Trigêmeo
/
Cálcio
/
Neurônios
Limite:
Animals
Idioma:
En
Ano de publicação:
2019
Tipo de documento:
Article