:BKKCA 


NEURON {
	SUFFIX bkkcasiz
	USEION k READ ek WRITE ik
	USEION cac READ caci VALENCE 2 
	RANGE G, g
	RANGE minf, taum, i
	RANGE kca
}

UNITS {
	(mA) = (milliamp)
	(mV) = (millivolt)
}

PARAMETER {
	g = 0.012 (siemens/cm2) <0,1e9>

	f = 0.08    :(mV/uM)
	
	koa = 0.4  (1/msec)
	kob = 0.2 (1/msec)
	kCa = 0.36  (1/msec)
	
	Vao1 =   -5 (mV)
	Vao2 = -5 (mV)
	
	sao1 = -15   :-23 (mV)
	sao2 = -9    :-5 (mV)
	
	c1 = 0.0001  :3.2  : 2.5  :(uM)
	c2 =  14  :(uM)
	c3 =  15  :(uM)
}

ASSIGNED {
	v (mV)
	caci
	ek (mV)
	i
	ik (mA/cm2)
	G (siemens/cm2)
}

STATE {
	a b
}

BREAKPOINT {
	SOLVE states METHOD cnexp
	G = g*a*b
	i = G*(v-ek)
	ik = i
}

INITIAL {
	a = ainf(v,caci)
	b = binf(caci)
}

DERIVATIVE states {
	a' = (ainf(v,caci)-a)*koa
	b' = (binf(caci)-b)*kob
}

FUNCTION ainf(v(mV),ca) {
	ainf = 1/(1+exp((v-Vao1+f*ca)/sao1))*1/(1+exp((v-Vao2+f*ca)/sao2))*(ca/(c1+ca))
}

FUNCTION binf(ca) {
	binf = c2/(c3+ca)
}