IFIBYNE   05513
INSTITUTO DE FISIOLOGIA, BIOLOGIA MOLECULAR Y NEUROCIENCIAS
Unidad Ejecutora - UE
artículos
Título:
Graded boosting of synaptic signals by low-threshold voltage-activated calcium conductance
Autor/es:
MARTÍN CARBÓ TANO; MARÍA EUGENIA VILARCHAO; LIDIA SZCZUPAK.
Revista:
JOURNAL OF NEUROPHYSIOLOGY
Editorial:
AMER PHYSIOLOGICAL SOC
Referencias:
Lugar: Bethesda; Año: 2015 vol. 114 p. 332 - 340
ISSN:
0022-3077
Resumen:
Low-threshold voltage-activatedcalcium conductances (LT-VACCs) play a substantial role in shapingthe electrophysiological attributes of neurites. We have investigatedhow these conductances affect synaptic integration in a premotornonspiking (NS) neuron of the leech nervous system. These cellsexhibit an extensive neuritic tree, do not fire Na-dependent spikes,but express an LT-VACC that was sensitive to 250 MNi2 and 100M NNC 55-0396 (NNC). NS neurons responded to excitation ofmechanosensory pressure neurons with depolarizing responses forwhich amplitude was a linear function of the presynaptic firingfrequency. NNC decreased these synaptic responses and abolished theconcomitant widespread Ca2 signals. Coherent with the interpretationthat the LT-VACC amplified signals at the postsynaptic level, thisconductance also amplified the responses of NS neurons to directinjection of sinusoidal current. Synaptic amplification thus is achievedvia a positive feedback in which depolarizing signals activate anLT-VACC that, in turn, boosts these signals. The wide distribution ofLT-VACC could support the active propagation of depolarizing signals,turning the complex NS neuritic tree into a relatively compactelectrical compartment.