Ribbon Synapse (Sikora et al 2005)

 Download zip file   Auto-launch 
Help downloading and running models
Accession:50997
A model of the ribbon synapse was developed to replicate both pre- and postsynaptic functions of this glutamatergic juncture. The presynaptic portion of the model is rich in anatomical and physiological detail and includes multiple release sites for each ribbon based on anatomical studies of presynaptic terminals, presynaptic voltage at the terminal, the activation of voltage-gated calcium channels and a calcium-dependent release mechanism whose rate varies as a function of the calcium concentration that is monitored at two different sites which control both an ultrafast, docked pool of vesicles and a release ready pool of tethered vesicles. See paper for more and details.
Reference:
1 . Sikora MA, Gottesman J, Miller RF (2005) A computational model of the ribbon synapse. J Neurosci Methods 145:47-61 [PubMed]
Model Information (Click on a link to find other models with that property)
Model Type: Synapse;
Brain Region(s)/Organism:
Cell Type(s): Retina ganglion GLU cell; Retina bipolar GLU cell;
Channel(s): I L high threshold;
Gap Junctions:
Receptor(s): AMPA; NMDA;
Gene(s):
Transmitter(s): Glutamate;
Simulation Environment: NEURON;
Model Concept(s): Intrinsic plasticity; Calcium dynamics;
Implementer(s): Sikora, Michael [Sikora at umn.edu];
Search NeuronDB for information about:  Retina ganglion GLU cell; Retina bipolar GLU cell; AMPA; NMDA; I L high threshold; Glutamate;
TITLE L-type calcium channel for Goldfish Bipolar cell
:
: Modified from Fohlmeister et al, 1990, Brain Res 510, 343-345
:

INDEPENDENT {t FROM 0 TO 1 WITH 1 (ms)}

NEURON {
	SUFFIX gfbp
	USEION ca READ cai, eca, cao WRITE ica
	RANGE gcabar
	RANGE c_inf
	RANGE tau_c
	RANGE c_exp

}


UNITS {
	(molar) = (1/liter)
	(mM) = (millimolar)
	(mA) = (milliamp)
	(mV) = (millivolt)

}

PARAMETER {
	gcabar	= 0.002	(mho/cm2)
	eca		(mV)
	cao	= 1.8	(mM)
	cai     = 0.0001 (mM)
	dt              (ms)
	v               (mV)

}

STATE {
	c 
}

INITIAL {
: The initial values were determined at a resting value of -66.3232 mV in a single-compartment
:	c = 0.0016
: at -60 mV
        c = 0.0038
}

ASSIGNED {
	ica	(mA/cm2)
	c_inf
	tau_c
	c_exp

}

BREAKPOINT {
	SOLVE states
	ica = gcabar * c*c*c * (v - eca)

}

PROCEDURE states() {	: exact when v held constant
	evaluate_fct(v)
	c = c + c_exp * (c_inf - c)

	VERBATIM
	return 0;
	ENDVERBATIM

}

UNITSOFF

PROCEDURE evaluate_fct(v(mV)) { LOCAL a,b
	
:CA channel
 a = (-0.3 * (v+10)) / ((exp(-0.1*(v+10))) - 1) : for Goldfish Bipolar
 b = 10 * (exp((-1*(v + 38))/9))


	tau_c = 1 / (a + b)
	c_inf = a * tau_c

: State vars to inifinity
	c_exp = 1 - exp(-dt/tau_c)

}

UNITSON

Loading data, please wait...