%0 Journal Article
%T Circuito el¨¦ctrico equivalente de una ves¨ªcula sin¨¢ptica Electric Circuit Equivalent to a Synaptic Vesicle
%A Cort¨¦s Xaira
%A Fayad Ram¨®n
%J Acta Biol¨®gica Colombiana
%D 2003
%I Universidad Nacional de Colombia
%X En el presente trabajo se desarrolla un modelo el¨¦ctrico de uno de los elementosprimordiales en la sinapsis nerviosa: la ves¨ªcula sin¨¢ptica. Dicha ves¨ªcula se consideracomo un organelo esferoidal, despojada de neurotransmisores y se asume, adem¨¢s, quesu lumen, su membrana y el citoplasma neuronal se comportan como medios lineales,homog¨¦neos e isotr¨®picos caracterizados por conductividades y permitividades espec¨ª-ficas. El m¨¦todo utilizado ser¨¢ la aplicaci¨®n te¨®rica de un campo el¨¦ctrico (que var¨ªa enel tiempo a bajas frecuencias) sobre esta ves¨ªcula, lo que induce a trav¨¦s de su membra-na una diferencia de potencial cuya caracterizaci¨®n se obtiene a partir de las ecuacionesde Maxwell sometidas a condiciones de contorno adecuadas, en la denominada aproxi-maci¨®n cuasi-estacionaria. A su vez, mediante aplicaci¨®n de la Transformada de Laplacea las expresiones resultantes se obtiene la FUNCI¨®N DE TRANSFERENCIA, que condu-ce a sintetizar un circuito RLC equivalente de la ves¨ªcula en estudio. El modelo predicevalores de capacitancia para ves¨ªculas esf¨¦ricas individuales que, al ser contrastados conlos que presenta la literatura existente derivada de procesos experimentales previos,alienta la perseverancia en este enfoque te¨®rico germinal. In the present work an electrical model of the synaptic vesicle is developed. The vesicleis considered as a spheroidal organelle without neurotransmitters in its inner space. Inaddition, its lumen, its membrane and the neuronal cytoplasm behave like linear,homogenous and isotropic media characterized by specific conductivities and permi-tivities. The theoretical approach considers the application of an electric field (varying intime at low frequencies) on this vesicle. A transmembrane potential difference is inducedand its characterization is obtained from Maxwell's equations subject to appropriateboundary conditions, in the so-called quasi-stationary approach. By applying theLaplace Transform to the resulting equations, the TRANSFER FUNCTION is obtained.In this way, we were able to synthesize an RLC circuit equivalent of the vesicle understudy. The model predicts capacitance values for individual spherical vesicles, whichcontrasted with those reported in the existing literature from previous experimentalprocesses, encourages the continuity of this theoretical approach.
%K Synaptic Vesicle
%K Equivalent Electric Circuit
%K Exocytosis
%U http://revistas.unal.edu.co/index.php/actabiol/article/view/26109