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
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treatment.fnc
xaleak.vdg
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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< fBR		>>
		>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
		>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>


		>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
fBR:		> 	Modulation by regulator				>
		>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

>----------------------->----------------------------------------------->
	1		>	fBR = BR			(1)	>
			>						>
>----------------------->----------------------------------------------->
>	2		>	fBR = 1 + BR			(2)	>
>			>						>
>----------------------->----------------------------------------------->
>	3		>		 1				>
>	500	>ß<	>	fBR = ----------------		(3)	>
>			>	     1 + ß x BR				>
>			>						>
>----------------------->----------------------------------------------->


		>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
BR:		> 	Modulation by regulator				>
		>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

>----------------------->----------------------------------------------->
>	1		>	dBR    Creg - BR			>
>	-1	>IV<	>	--- = ----------		(1)	>
>	.001	>u<	>	dt       u				>
>			>						>
>----------------------->----------------------------------------------->
	2		>	      Creg				>
>	100.0	>a<	>	BR = ----------			(2)	>
>	160.0	>a<	>	BR = ----------			(2)	>
	100	
			>	     a + Creg				>
			>						>
>----------------------->----------------------------------------------->
>	3		>	            Creg			>
>	20	>a<	>	BR = 1 + ---------		(3)	>
>			>	          a + Creg			>
>			>						>
>----------------------->----------------------------------------------->
>	4		>		1				>
>	0.04	>ß<	>	BR = ------------		(4)	>
>			>	     1 + ß x Creg			>
>			>						>
>			>						>
>----------------------->----------------------------------------------->
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