;; Akemann W, Knopfel T. Interaction of Kv3 potassium channels and
;; resurgent sodium current influences the rate of spontaneous firing of
;; Purkinje neurons. J Neurosci. 2006 Apr 26;26(17):4602-12.

(nemo-model CaBK

  ((input v 
	  (cai from ion-pools))
	     
   (const Vrest   = -68)

   (const celsius = 24)
   
   (const temp_adj = (pow (3 ((celsius - 22) / 10))))

   (component (type ion-channel) (name CaBK)
	      
	      (component (type gate)
			 
			 ;; rate functions
			 
			 (defun CaBK_zinf (ca)  
			   (let ((zhalf 0.001))
			     (1 / (1 + (zhalf / ca)))))

			 (const CaBK_ztau = 1.0)
			 
			 (defun CaBK_minf (v)
			   (let ((cvm  28.9)
				 (ckm  6.2))
			     (1.0 / (1.0 + exp (neg ((v + 5.0 + cvm) / ckm))))))
			 
			 (defun CaBK_mtau (v)
			   (let ((ctm     0.000505)
				 (cvtm1   86.4)
				 (cktm1   -10.1)
				 (cvtm2   -33.3)
				 (cktm2   10))
			     (ctm + (1.0 / (exp (neg ((v + 5.0 + cvtm1) / cktm1)) +
						exp (neg ((v + 5.0 + cvtm2) / cktm2)))))))
			 
			 (defun CaBK_hinf (v) 
			   (let ((ch    0.085)
				 (cvh   32)
				 (ckh   -5.8))
			     (ch + ((1.0 - ch) / (1.0 + (exp (neg ((v + 5.0 + cvh) / ckh))))))))
			 
			 (defun CaBK_htau (v)
			   (let ((cth     0.0019)
				 (cvth1   48.5)
				 (ckth1   -5.2)
				 (cvth2   -54.2)
				 (ckth2   12.9))
			     (cth + (1.0 / (exp (neg ((v + cvth1) / ckth1)) +
						exp (neg ((v + cvth2) / ckth2)))))))
			 
			 (reaction
			  (CaBK_z
			   (transitions (<-> C O (CaBK_zinf (cai) / CaBK_ztau)
					     ((1 - CaBK_zinf (cai)) / CaBK_ztau)))
			   (initial   (CaBK_zinf (1e-4)))
			   (open O)  (power 2)))
			 
			 (output CaBK_z )  

			 
			 (hh-ionic-gate 
			  (CaBK  ;; ion name: exported variables will be of the form {ion}_{id}
			   (initial-m  (CaBK_minf (Vrest) / temp_adj))
			   (initial-h  (CaBK_hinf (Vrest) / temp_adj))
			   (m-power    3)
			   (h-power    1)
			   (m-inf      (CaBK_minf (v) / temp_adj) )
			   (m-tau      (CaBK_mtau (v) / temp_adj) )
			   (h-inf      (CaBK_hinf (v) / temp_adj) )
			   (h-tau      (CaBK_htau (v) / temp_adj) )))
			 
			 )
	      
	      (component (type pore)
			 (const  gbar_CaBK  = 0.014)
			 (output gbar_CaBK ))
	      
	      (component (type permeating-ion) (name k)
			 (const e_CaBK = -85)
			 (output e_CaBK ))
	      
	      ) ;; end BK current

   ))