Enhanced Excitability in Hermissenda: modulation by 5-HT (Cai et al 2003)

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Accession:34163
Serotonin (5-HT) applied to the exposed but otherwise intact nervous system results in enhanced excitability of Hermissenda type-B photoreceptors. Several ion currents in the type-B photoreceptors are modulated by 5-HT, including the A-type K+ current (IK,A), sustained Ca2+ current (ICa,S), Ca-dependent K+ current (IK,Ca), and a hyperpolarization-activated inward rectifier current (Ih). In this study,we developed a computational model that reproduces physiological characteristics of type B photoreceptors, e.g. resting membrane potential, dark-adapted spike activity, spike width, and the amplitude difference between somatic and axonal spikes. We then used the model to investigate the contribution of different ion currents modulated by 5-HT to the magnitudes of enhanced excitability produced by 5-HT. See paper for results and more details.
Reference:
1 . Cai Y, Baxter DA, Crow T (2003) Computational study of enhanced excitability in Hermissenda: membrane conductances modulated by 5-HT. J Comput Neurosci 15:105-21 [PubMed]
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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): Hermissenda photoreceptor Type B;
Channel(s): I Na,t; I L high threshold; I N; I A; I K; I h; I K,Ca; I Calcium; I A, slow;
Gap Junctions: Gap junctions;
Receptor(s):
Gene(s):
Transmitter(s): Serotonin;
Simulation Environment: SNNAP;
Model Concept(s): Activity Patterns; Action Potentials; Invertebrate;
Implementer(s): Cai, Yidao;
Search NeuronDB for information about:  I Na,t; I L high threshold; I N; I A; I K; I h; I K,Ca; I Calcium; I A, slow; Serotonin;
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Cai
readme.txt
00note.txt
axona.neu
axona2axonb.es
axonb.neu
axonb2axonc.es
axonc.neu
axonc2term.es
bph.ntw
bph.ntw_genp
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bph.ous3
bph.ous4
bph.smu
bph.trt
bph.trt_casmod
bph.trt_Drmod
bph.trt_Iamod
bph.trt_Ihmod
bph.trt_Ikcamod
bph.trt_light
bph.trt_mixmod
bph.trt_Ri
bph.trt_std
bph.trt_vclamp
bph.trt0
bph_casmod.smu
bph_Drmod.smu
bph_genp.smu
bph_Iamod.smu
bph_Ihmod.smu
bph_Ikcamod.smu
bph_mixmod.smu
bph_Ri.smu
bph_stdmod.smu
ca.A
ca.B
Ca.ion
ca.vdg *
Ca2Ikca.fBR
cat.A
cat.B
cat.vdg
design.txt
Dr.A
Dr.B
Dr.vdg
exp.es
exp1.fnc
exp2.fnc
exp3.fnc
grf.def
Ia.A
Ia.A_bak
Ia.B
Ia.vdg
Ikca.A
Ikca.B
Ikca.vdg *
Ir.A
Ir.vdg
leak.vdg
mv.neu
mv2soma.es
mvleak.vdg
Na.A
Na.B *
Na.vdg
ousgrf.def
simufiles.usd
soma.neu
soma2axona.es
tCa.ion
tca.vdg *
tCa2Ikca.fBR
tcat.vdg *
tDr.vdg
term.neu
term.neu_bak
tIa.vdg
tIkca.vdg *
tIr.vdg
tleak.vdg
tmp.1
tmp.ps
tNa.A
tNa.B
tNa.vdg
treatment.fnc
xaleak.vdg
xbCa.ion *
xbca.vdg *
xbCa2Ikca.fBR
xbcat.vdg *
xbDr.vdg *
xbIa.vdg *
xbIkca.vdg *
xbIr.vdg
xbleak.vdg
xbNa.A *
xbNa.B *
xbNa.vdg *
xcCa.ion *
xcca.vdg *
xcCa2Ikca.fBR
xccat.vdg *
xcDr.vdg *
xcIa.vdg *
xcIkca.vdg *
xcIr.vdg
xcleak.vdg
xcNa.A *
xcNa.B *
xcNa.vdg *
                            
		>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
		>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
		>>    modules name< ION		>>
		>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
		>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>


		>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Cion:		> 	Concentration of an ion				>
		>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

>----------------------->------------------------------------------------------>
>	1		>						       >
>	100	>Vc< 	>				-------		       >
>	220	>K1<	>				       \	       >
>	20	>K2<	>				        \	       >
>	1	>K3<	>	dCion     CIion - Iu - Id	|	       >
>	1	>Dgain<	>	----- = -----------------	|	       >
>	1	>Dmid<	>	 dt             Vc		|	       >
>	1	>p<	>					|	       >
>			>		     +--       -+	|	       >
>			>		     | -------  |	|	       >
>			>		     | \        |	|	       >
>			>	CIion = K1 x |- > Iion  | - K2	|	       >
>			>		     | /        |	 >	(1)    >
>			>		     | -------  |	|	       >
>			>		     +--       -+	|	       >
>			>					|	       >
>			>		Dgain			|	       >
>			>	Iu = ---------------		|	       >
>			>			    p		|	       >
>			>		1+ dmid/Cion		|	       >
>			>					|	       >
>			>	Id = K3 x Cion			|	       >
>			>					/	       >
>			>				       /	       >
>			>				-------		       >
>			>						       >
>----------------------->------------------------------------------------------>
	2
>	8
	0
	.7
	140
			>		    |     +-	    -+       |	       >
>       .5    >.1 K1<	>		    |     | -------  |	     |	       >
>    100   >300 K2<	>	dCion	    |     | \        |	     |	       >
			>	-----= K1 x |K2 x |- > Iion  | -Cion |	(2)    >
			>	 dt	    |     | /        |	     |	       >
			>		    |     | -------  |	     |	       >
			>		    |     +-	    -+       |	       >
			>		    +--		           --+	       >
			>						       >
>----------------------->------------------------------------------------------>
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