Bursting excitable cell models by a slow Ca2+ current

✍ Scribed by Teresa Ree Chay

• Publisher: Elsevier Science
• Year: 1990
• Tongue: English
• Weight: 521 KB
• Volume: 142
• Category: Article
• ISSN: 0022-5193
• DOI: 10.1016/s0022-5193(05)80555-7

✦ Synopsis

Bursting in excitable cells is a phenomenon that has attracted the interest of many electrophysiologists and non-linear dynamicists. In this paper, we present two models that give rise to bursting in action potentials. The membrane of the first model contains a voltage-activated Ca ~-+ channel that inactivates very slowly upon depolarization and a delayed K ÷ channel that is activated by voltage. This model consists of three dynamic variables--the gating variable of K + channel (n), inactivation gating variable of the Ca 2+ channel (f), and membrane potential (V). The membrane of the second model contains a voltage-activated Na ÷ channel that inactivates rather fast upon depolarization. This model contains altogether five dynamic variables--the Na + inactivation gating variable (h) and Ca 2÷ activation variable (d), in addition to the three dynamic variables in the first model. With the first model, we show how various interesting bursting patterns may arise from such a simple three dynamic variable model. We also demonstrate that a slowly inactivating voltage-dependent Ca 2+ channel may play the key role in the genesis of bursting. With the second model, we show how the participation of a quickly inactivating fast inward current may lead to a neuronal type of bursting, multi-peaked oscillations, and chaos, as the rates of the gating variables change.