;; Reference: Theta-Frequency Bursting and Resonance in Cerebellar Granule Cells:Experimental
;; Evidence and Modeling of a Slow K+-Dependent Mechanism
;; Egidio D'Angelo,Thierry Nieus,Arianna Maffei,Simona Armano,Paola Rossi,Vanni Taglietti,
;; Andrea Fontana and Giovanni Naldi

(nemo-model CGC_Nar

  (
   (input v
    (cai from ion-pools)
    (ica from ion-currents))

   (const Vrest = -68)
	     
   (const fix_celsius = 30)

   (component (type ionic-current) (name Nar )
	      
	      (component (type gate)

			 ;; rate constants
			 (const Q10 = (pow (3 ((fix_celsius - 20) / 10))))

			 (const Aalpha_s     = -0.00493)
			 (const V0alpha_s    = -4.48754)
			 (const Kalpha_s     = -6.81881)
			 (const Shiftalpha_s = 0.00008)

			 (const Abeta_s     = 0.01558)
			 (const V0beta_s    = 43.97494)
			 (const Kbeta_s     =  0.10818)
			 (const Shiftbeta_s = 0.04752)

			 (const Aalpha_f  = 0.31836)
			 (const V0alpha_f = -80)
			 (const Kalpha_f  = -62.52621)

			 (const Abeta_f  = 0.01014)
			 (const V0beta_f = -83.3332)
			 (const Kbeta_f  = 16.05379)

			 ;; rate functions
			 (defun alpha_s (v) 
			   (Q10 * (Shiftalpha_s + (Aalpha_s * ((v + V0alpha_s) )) ) / (exp ((v + V0alpha_s) / Kalpha_s) - 1)))

			 (defun beta_s (v) 
			   (Q10 * (Shiftbeta_s + Abeta_s * ((v + V0beta_s) / (exp((v + V0beta_s) / Kbeta_s) - 1)))))

			 (defun alpha_f (v) 
			   (Q10 * Aalpha_f * exp( ( v - V0alpha_f ) / Kalpha_f)))

			 (defun beta_f (v) 
			   (Q10 * Abeta_f * exp( ( v - V0beta_f ) / Kbeta_f )  ))

			 (hh-ionic-gate 
			  (Nar  ;; ion name: exported variables will be of the form {ion}_{id}
			   (initial-m  ((alpha_s (v)) / (alpha_s (v) + beta_s (v)) ))
			   (initial-h  ((alpha_f (v)) / (alpha_f (v) + beta_f (v)) ))
			   (m-power    1)
			   (h-power    1)
			   (m-alpha    (alpha_s (v)))
			   (m-beta     (beta_s (v)))
			   (h-alpha    (alpha_f (v)))
			   (h-beta     (beta_f (v)))
			   ))
			 )

	      (component (type pore)
			 (const  gbar  = 0.0005)
			 (output gbar ))

	      (component (type permeating-ion) (name na)
			 (const e = 87.39)
			 (output e ))
	      
	      ) ;; end Nar current


   (component (type voltage-clamp) (name Nar)

	      (const vchold   = -71)
	      (const vcbase   = -60)
	      (const vcinc    = 10)
	      (const vcsteps  = 9)
	      (const vchdur   = 30)
	      (const vcbdur   = 100)
           
	      (output vchold vcbase vcinc vcsteps vchdur vcbdur))

))