Neuronal cell firing is crucial to nerve-nerve communication. The ability to produce consecutive action potentials is related to the activation of inward currents after each upstroke. If fast Na current is indeed responsible for the overshoot, it is still unclear which current drives membrane voltage to the Na threshold. In this study we present evidence that in adult rat sensory neurones a dihydropyridine-sensitive Ca channel exists in addition to the well characterized L-type, or high-threshold Ca channel. During stimulated action potential trains, L-type Ca channels open during the excitation wave, whereas activity of the other dihydropyridine-sensitive Ca channel was observed primarily between action potentials. This second Ca pathway shows remarkably long openings at negative potentials after a series of positive prepulses. The nerve action potential and the repetitive firing work as a physiological Ca channel facilitation mechanism. Therefore, we suggest that this novel Ca conductance provides inward current, between two consecutive action potentials, able to modulate the frequency of neuronal bursts.

Functional role of low-voltage-activated dihydropyridine-sensitive Ca channels during the action potential in adult rat sensory neurones / A. Ferroni, A. Galli, M. Mazzanti. - In: PFLÜGERS ARCHIV. - ISSN 0031-6768. - 431:6(1996), pp. 954-963.

Functional role of low-voltage-activated dihydropyridine-sensitive Ca channels during the action potential in adult rat sensory neurones

M. Mazzanti
1996

Abstract

Neuronal cell firing is crucial to nerve-nerve communication. The ability to produce consecutive action potentials is related to the activation of inward currents after each upstroke. If fast Na current is indeed responsible for the overshoot, it is still unclear which current drives membrane voltage to the Na threshold. In this study we present evidence that in adult rat sensory neurones a dihydropyridine-sensitive Ca channel exists in addition to the well characterized L-type, or high-threshold Ca channel. During stimulated action potential trains, L-type Ca channels open during the excitation wave, whereas activity of the other dihydropyridine-sensitive Ca channel was observed primarily between action potentials. This second Ca pathway shows remarkably long openings at negative potentials after a series of positive prepulses. The nerve action potential and the repetitive firing work as a physiological Ca channel facilitation mechanism. Therefore, we suggest that this novel Ca conductance provides inward current, between two consecutive action potentials, able to modulate the frequency of neuronal bursts.
Action potential; Calcium ions; Dorsal root ganglia; Electrophysiology; Ionic channels; Patch-clamp; 3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; Action Potentials; Animals; Calcium Channel Agonists; Calcium Channels; Dihydropyridines; Electric Conductivity; Electrophysiology; Ganglia, Spinal; In Vitro Techniques; Membrane Potentials; Neurons, Afferent; Rats
Settore BIO/09 - Fisiologia
1996
Article (author)
File in questo prodotto:
Non ci sono file associati a questo prodotto.
Pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/717772
Citazioni
  • ???jsp.display-item.citation.pmc??? 4
  • Scopus 9
  • ???jsp.display-item.citation.isi??? 10
social impact