Serotonergic modulation of Aplysia sensory neurons (Baxter et al 1999)

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Accession:33986
The present study investigated how the modulation of these currents altered the spike duration and excitability of sensory neurons and examined the relative contributions of PKA- and PKC-mediated effects to the actions of 5-HT. A Hodgkin-Huxley type model was developed that described the ionic conductances in the somata of sensory neurons. The descriptions of these currents and their modulation were based largely on voltageclamp data from sensory neurons. Simulations were preformed with the program SNNAP (Simulator for Neural Networks and Action Potentials). The model was sufficient to replicate empirical data that describes the membrane currents, action potential waveform and excitability as well as their modulation by application of 5-HT, increased levels of adenosine cyclic monophosphate or application of active phorbol esters. The results provide several predictions that warrant additional experimental investigation and illustrate the importance of considering indirect as well as direct effects of modulatory agents on the modulation of membrane currents. See paper for more details.
Reference:
1 . Baxter DA, Canavier CC, Clark JW, Byrne JH (1999) Computational model of the serotonergic modulation of sensory neurons in Aplysia. J Neurophysiol 82:2914-35 [PubMed]
Model Information (Click on a link to find other models with that property)
Model Type: Neuron or other electrically excitable cell;
Brain Region(s)/Organism:
Cell Type(s): Aplysia sensory neuron;
Channel(s): I Na,t; I A; I K; I K,Ca; I CAN; I Potassium;
Gap Junctions:
Receptor(s):
Gene(s):
Transmitter(s): Serotonin;
Simulation Environment: SNNAP;
Model Concept(s): Action Potentials; Invertebrate;
Implementer(s): Baxter, Douglas;
Search NeuronDB for information about:  I Na,t; I A; I K; I K,Ca; I CAN; I Potassium; Serotonin;
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Baxter
README.txt
5HT.neu
5HT_Ca_L.vdg *
5HT_K_V.A
5HT_K_V.B *
5HT_K_V.vdg
5HT_Kcas.vdg *
5HT_Ks_I.vdg
5HT_Ks_V.vdg
ASW.neu
Baxter_excite.jpg
Ca.ion
Ca_L.A
Ca_L.B
Ca_L.vdg
Ca_N.A
Ca_N.B
Ca_N.vdg
Ca2Ca_L.fBR
Ca2Ca_N.fBR
Ca2Kcaf.fBR
Ca2Kcas.fBR
cAMP.neu
cAMP_Ca_L.vdg *
cAMP_K_V.A
cAMP_K_V.vdg
cAMP_Kcas.vdg *
cAMP_Ks_I.vdg
cAMP_Ks_V.vdg
excite.ntw
excite.ous
excite.smu
excite.trt
K_A.A
K_A.B
K_A.vdg
K_V.A
K_V.B
K_V.vdg
Kcaf.A
Kcaf.vdg
Kcas.vdg
Ks_I.vdg
Ks_V.A
Ks_V.vdg
leak.vdg
Na.A
Na.B
Na.vdg
ousgrf.def *
phorbol.neu
phorbol_Ca_L.vdg
phorbol_K_V.A
phorbol_K_V.B *
phorbol_K_V.vdg
phorbol_Kcas.vdg
phorbol_Ks_I.vdg
phorbol_Ks_V.vdg
simufiles.usd
spike.ntw
spike.ous
spike.smu
spike.trt
TEA.neu
TEA_Kcaf.vdg
TEA_Kcas.vdg
                            
		>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
		>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
		>>    module's name: B		>>
		>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
		>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

>----------------------------------------------------------------------->

		>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
B:		> 	Inactivation function (time constant method)	>
		>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

>------------------------------->--------------------------------------->
>				>					>
>	1			>	B = ssB			(1)	>
>				>					>
>------------------------------->--------------------------------------->
	2			>	        ssB - B			>
	0.94	>IV<		>	dB/dt= ------------	(2)	>
				>	           tB			>
>------------------------------->--------------------------------------->



		>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
ssB:		> 	Steady state value for activation		>	
		>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

>----------------------->------------------------------------------------------>
	1		>			1			       >
       -15.0	>-15 h<	>	ssB = --------------------		(1)    >
	11.0	 >11 s<	>		+-	     -+ p	  	       >
	1	 >1 p<	>		|     (V-h)/s |			       >
			>		|1 + e        |			       >
			>		+-	     -+			       >
			>						       >
>----------------------->------------------------------------------------------>
>	2		>		   1 - Bn			       >
>	xx	>Bn<	>	ssB = -------------------- + Bn		       >
>	xx	>h<	>		+-	     -+ p		       >
>	xx	>s<	>		|     (V-h)/s |			(2)    >
>	xx	>p<	>		|1 + e        |			       >
>			>		+-	     -+			       >
>----------------------->------------------------------------------------------>


		>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
tB:		> 	Time constant for activation			>	
		>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

>----------------------->------------------------------------------------------>
>	1		> tB = tx					    (1)>
>	 xx >tx<	>						       >
>----------------------->------------------------------------------------------>
>	2		>	  tx -tn				       >
>	 xx >tx<	> tB = -------------------- + tn	            (2)>
>	 xx >tn<	>	+-	     -+ p			       >
>	 xx >h<		>	|     (V-h)/s |				       >
>	 xx >s<		>	|1 + e        |				       >
>	 xx >p<		>	+-	     -+				       >
>			>						       >
>----------------------->------------------------------------------------------>
	3		>	 		tx -tn			       >
    0.62       >.62 tx<	> tB = ----------------------------------- + tn     (3)>
    0.00372  >.0037 tn<	>	+-	     -+p1 +-	       -+p2	       >
  -18.0        >-18 h1<	>	|   (V-h1)/s1 |	  |   (V-h2)/s2 |	       >
   18.0         >18 s1<	>	|1+e          |	  |1+e          |	       >
    1            >1 p1<	>	+-	     -+	  +-	       -+	       >
  -20.0        >-20 h2<	>						       >
  -15.0        >-15 s2<	>						       >
    1            >1 p2<	>						       >
>----------------------->------------------------------------------------------>
> 	4		>	  |   1 - rtn		       |	       >
>	 xx 	>tx<	> tB = tx | -------------------- + rtn |            (4)>
> 	 xx 	>rtn<	>	  | +-	          -+ p	       |	       >
> 	 xx 	>h<	>	  | |     (V-h)/s  |	       |	       >
> 	 xx 	>s<	>	  | |1 + e         |	       |	       >
> 	 xx 	>p<	>	  | +-	          -+           |	       >
> 			>	  +-- 			      -+	       >
> 			>						       >
>----------------------->------------------------------------------------------>
>	5		>	| 	1 - rtn	 	                  |    >
>	 xx	>tx<	> tB=tx | ---------------------------------- +rtn | (5)>
>	 xx	>rtn<	>	| +-	      -+p1+-	      -+p2        |    >
>	 xx	>h1<	>	| |   (V-h1)/s1|  |   (V-h2)/s2|          |    >
>	 xx	>s1<	>	| |1+e         |  |1+e         |          |    >
>	 xx	>p1<	>	| +-	      -+  +-	      -+          |    >
>	 xx	>h2<	>	+-- 			   	         -+    >
>	 xx	>s2<	>						       >
>	 xx	>p2<	>						       >
>----------------------->------------------------------------------------------>

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