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.
Model Type: Neuron or other electrically excitable cell
Cell Type(s): Hermissenda photoreceptor Type B
Currents: I Na,t; I L high threshold; I N; I A; I K; I h; I K,Ca; I Calcium; I A, slow
Transmitters: Serotonin
Model Concept(s): Activity Patterns; Action Potentials; Invertebrate
Simulation Environment: SNNAP
Implementer(s): Cai, Yidao
References:
Cai Y, Baxter DA, Crow T. (2003). Computational study of enhanced excitability in Hermissenda: membrane conductances modulated by 5-HT. Journal of computational neuroscience. 15 [PubMed]