9-Phenanthrol modulates postinhibitory rebound and afterhyperpolarizing potentials in an excitatory motor neuron of the medicinal leech.
J Comp Physiol A Neuroethol Sens Neural Behav Physiol
; 203(8): 613-633, 2017 Aug.
Article
em En
| MEDLINE
| ID: mdl-28497254
ABSTRACT
Postinhibitory rebound (PIR) responses in leech dorsal excitatory motor neurons (cell DE-3) are eliminated by Ca2+ channel blockers but also exhibit a strong dependence on extracellular Na+. These features could be explained by a voltage-gated Ca2+ current acting in concert with a Ca2+-activated nonspecific current (ICAN). In vertebrates, ICAN is associated with TRPM4 channels which are blocked selectively by 9-phenanthrol. Here, we show that 9-phenanthrol selectively inhibits a late phase of PIR and simultaneously enhances afterhyperpolarizing potentials (AHPs). Bath application of NNC 55-0396 or Cd2+ combined with ion substitution experiments indicate that a low-voltage-activated Ca2+ current plays a key role in generating PIR and that Ca2+ influx through low- or high-voltage-activated Ca2+ channels can trigger AHPs via activation of a Ca2+-dependent K+ current. We also demonstrate modulation of rebound responses by other ICAN blockers such as gadolinium and flufenamic acid, as well as the calmodulin antagonist W-7. We discuss how these results provide additional insights into the specific types of ionic currents underlying rebound responses of motor neuron DE-3 in the medicinal leech.
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Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Fenantrenos
/
Hirudo medicinalis
/
Neurônios Motores
Limite:
Animals
Idioma:
En
Revista:
J Comp Physiol A Neuroethol Sens Neural Behav Physiol
Assunto da revista:
CIENCIAS DO COMPORTAMENTO
/
NEUROLOGIA
Ano de publicação:
2017
Tipo de documento:
Article
País de afiliação:
Estados Unidos