DHP receptor
The DHP receptor gene is almost identical to those that encode voltage-gated calcium channels.
(You may know that dihydropyridines are widely used antihypertensive drugs that reduce blood pressure by
inhibiting the calcium channels that provide the calcium influx that supports contraction - thus relaxing arterial smooth muscle)
Voltage-gated ion channels contain a region that serves as a voltage-sensor. This voltage-sensor is thought to be central to the way DHP receptors stimulate calcium release from the SR.