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
bph.ous
bph.ous_bak
bph.ous_genp
bph.ous_mod
bph.ous_Ri
bph.ous_sp
bph.ous_vclamp
bph.ous2
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: vdg		>>
		>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
		>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

		>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Ivd:		> 	Current due to a voltage-dependent conductance	>
		>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

>------------------------------->--------------------------------------->
				>		p			>
	1			>	G= g x A x B 		(1)	>
	cat.A		>A<	>					>
	cat.B		>B<	>					>
	1.5e-3     >S/cm2< >g<	>					>
>	2e-3      >S/cm2< >g<	>					>
>	4e-3      >S/cm2< >g<	>					>
>	2e-3      >S/cm2< >g<	>					>
>	4e-5      >S/cm2< >g<	>					>
>	.001      >.01< >g<	>					>
	3 		>P<	>	Ivd = G x (V -E)		>
	70.0 		>E<	>					>
				>					>
>------------------------------->--------------------------------------->
>				>		p			>
>	2			>	Ivd= g x m x h 		(2)	>
>	model.m		>m<	>					>
>	model.h		>h<	>					>
>	0.012 		>g<	>					>
>	1 		>P<	>	Ivd = G x (V -E)		>
>	35 		>E<	>					>
>				>					>
>------------------------------->--------------------------------------->
>
>				>		p			>
>	3			>	G= g x A		(3)	>
>	cat.A		>A<	>					>
>	.01 		>g<	>					>
>	3 		>P<	>	Ivd = G x (V -E)		>
>    70 >p.1330,JNsep94<>E<	>					>
>				>					>
>------------------------------->--------------------------------------->
>				>		p			>
>	4			>	Ivd= g x m 		(4)	>
>	model.m		>m<	>					>
>	0.012 		>g<	>					>
>	1 		>P<	>	Ivd = G x (V -E)		>
>	35 		>E<	>					>
>				>					>
>------------------------------->--------------------------------------->
>				>					>
>	5			>	Ivd = G x (V -E)	(5)	>
>	0.0012 		>g<	>					>
>	70 		>E<	>					>
>				>					>
>------------------------------->--------------------------------------->

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