Increases in the amount of cytoplasmic calcium required to initiate a muscle contraction are mediated by the coupling between a on the t tubule and a on the membrane of the sarcoplasmic reticulum.

1) Dihydropyridine receptor

2) Rynodine receptor

Explanation:

Rynodine receptor: It is a category of interacellular channels of calcium with different forms like neurons and muscles found in animal tissues.

Dihydropyridine receptor: they are present in muscle tissues and are able to sense voltage in skeleton muscles thus can increase or control the release of calcium.

oh it is true if thats what you are asking

i have no clue hope you find the answer