Leech S Cell: Modulation of Excitability by Serotonin (Burrell and Crisp 2008)

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Accession:102279
Serotonergic modulation of the afterhyperpolarization (AHP) contributes to the regulation of the excitability of the leech S cell, a neuron critical for sensitization of the shortening reflex. Pharmacological and physiological data suggest that three currents contribute to the S cell's afterhyperpolarization: a charybdotoxin-sensitive, fast calcium-dependent potassium current (fAHP); a tubocurare-sensitive, calcium-dependent potassium current (mAHP); and, a saxitoxin-sensitive, afterdepolarization current (ADP). This single-compartment model of the S cell is constructed using fAHP, mAHP and ADP currents, and shows that reduction of the conductances to mimic the effects of serotonin is sufficient to enhance excitability (repetitive firing).
Reference:
1 . Burrell BD, Crisp KM (2008) Serotonergic modulation of afterhyperpolarization in a neuron that contributes to learning in the leech. J Neurophysiol 99:605-16 [PubMed]
Model Information (Click on a link to find other models with that property)
Model Type: Axon;
Brain Region(s)/Organism:
Cell Type(s): Leech S cell;
Channel(s): I Na,t; I L high threshold; I K; I K,leak; I K,Ca; I Sodium;
Gap Junctions:
Receptor(s):
Gene(s):
Transmitter(s):
Simulation Environment: SNNAP;
Model Concept(s):
Implementer(s): Crisp, Kevin [crisp at stolaf.edu];
Search NeuronDB for information about:  I Na,t; I L high threshold; I K; I K,leak; I K,Ca; I Sodium;
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leechSCell
readme.txt
ADP.m *
ADP.vdg *
Ca.fBR *
Ca.ion *
Ca.ion.tmp *
Ca.m *
Ca.vdg *
fAHP.m *
fAHP.vdg *
Kdr.m *
Kdr.vdg *
leak.vdg
mAHP.A *
mAHP.vdg *
Na.h *
Na.m *
Na.vdg *
netwf *
netwfile *
ousgrf.def *
SCell.neu
SCell.ntw
simufiles.usd
single.ous
single.ous.mnu
single.smu
single.smu.exec
single.smu.hmn *
single.smu.ing
single.smu.out
single.smu.out.head
single.trt
singlezoom.ous
singlezoom.ous.mnu
singlezoom.smu
singlezoom.smu.exec
singlezoom.smu.hmn *
singlezoom.smu.ing
singlezoom.smu.out
singlezoom.smu.out.head
train.ous
train.ous.mnu
train.smu
train.smu.exec
train.smu.hmn *
train.smu.ing
train.smu.out
train.smu.out.head
train.trt
                            
		>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
		>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
		>>    module's name: A		>>
		>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
		>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>


		>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
A:		> 	Activation function (time constant method)	>
		>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

>------------------------------->--------------------------------------->
>				>					>
>	1			>	A = ssA			(1)	>
>				>					>
>------------------------------->--------------------------------------->
	2			>	        ssA - A			>>
	0.0	>IV<		>	dA/dt= ------------	(2)	>
				>	           tA			>
>------------------------------->--------------------------------------->

		>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
ssA:		> 	Steady state value for activation		>
		>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

>----------------------->------------------------------------------------------>
	1		>			1			       >
	-1.2	>h<	>	ssA = --------------------		(1)    >
	9.0	>s<	>		+-	     -+ p		       >
	1.0	>p<	>		|     (h-V)/s |			       >
			>		|1 + e        |			       >
			>		+-	     -+			       >
			>						       >
>----------------------->------------------------------------------------------>
>	2		>		   1 - An			       >
>	0.0001	>An<	>	ssA = -------------------- + An		       >
>	0.0002	>h<	>		+-	     -+ p		       >
>	0.0003	>s<	>		|     (h-V)/s |			(2)    >
>	0.00004	>p<	>		|1 + e        |			       >
>			>		+-	     -+			       >
>----------------------->------------------------------------------------------>


		>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
tA:		> 	Time constant for activation			>	
		>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

>----------------------->------------------------------------------------------>
>			>						       >
>	1		> tA = tx					    (1)>
>	0.0	>tx<	>						       >
>----------------------->------------------------------------------------------>
	2		>	  tx -tn				       >
	0.025	>tx<	> tA = -------------------- + tn	            (2)>
	0.0010	>tn<	>	+-	     -+ p			       >
	-8.7	>h<	>	|     (V-h)/s |				       >
	1.85	>s<	>	|1 + e        |				       >
	1.0	>p<	>	+-	     -+				       >
			>						       >
>----------------------->------------------------------------------------------>
>	3		>	 		tx -tn			       >
>	0.1	>tx<	> tA = ----------------------------------- + tn     (3)>
>	0.2	>tn<	>	+-	     -+p1 +-	       -+p2	       >
>	0.3	>h1<	>	|   (V-h1)/s1 |	  |   (V-h2)/s2 |	       >
>	0.4	>s1<	>	|1+e          |	  |1+e          |	       >
>	1	>p1<	>	+-	     -+	  +-	       -+	       >
>	0.5	>h2<	>						       >
>	0.6	>s2<	>						       >
>	2	>p2<	>						       >
>----------------------->------------------------------------------------------>
>			>	  +--			      -+	       >
>	4		>	  |   1 - rtn		       |	       >
>	xxx.xx	>tx<	> tA = tx | -------------------- + rtn |            (4)>
>	xxx.xx	>rtn<	>	  | +-	          -+ p	       |	       >
>	xxx.xx	>h<	>	  | |     (V-h)/s  |	       |	       >
>	xxx.xx	>s<	>	  | |1 + e         |	       |	       >
>	x	>p<	>	  | +-	          -+           |	       >
>			>	  +-- 			      -+	       >
>			>						       >
>----------------------->------------------------------------------------------>
>			>	+--			                --+    >
>	5		>	| 	1 - rtn		                  |    >
>	xxx.xx	>tx<	> tA=tx | ---------------------------------- +rtn | (5)>
>	xxx.xx	>rtn<	>	| +-	      -+p1+-	      -+p2        |    >
>	xxx.xx	>h1<	>	| |   (V-h1)/s1|  |   (V-h2)/s2|          |    >
>	xxx.xx	>s1<	>	| |1+e         |  |1+e         |          |    >
>	x	>p1<	>	| +-	      -+  +-	      -+          |    >
>	xxx.xx	>h2<	>	+-- 			   	        --+    >
>	xx.xx	>s2<	>						       >
>	x	>p2<	>						       >
>----------------------->------------------------------------------------------>

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