Module 7: Figure SMC cytosolic oscillator
Vascular smooth muscle cell oscillatory mechanism.
Activation of certain smooth muscle cells (SMCs), such as those in the vascular or airways are driven by an endogenous cytosolic oscillatory mechanism that generates periodic pulses of Ca2+ that usually appear as a propagating Ca2+ wave. The pacemaker is induced/modulated by neurotransmitters such as acetylcholine (ACh), 5-hydroxytryptamine (5-HT), noradrenaline (NA) and endothelin-1 (ET-1), which act through inositol 1,4,5-trisphosphate (InsP3) that is an essential feature of the cytosolic oscillator that generates the Ca2+ waves. See text for further details of the pacemaker mechanism and how it is modulated by a variety of ion channels.