Schematic drawing of the possible TRPV1 contribution in the maintenance of Ca²⁺ muscle homeostasis.

<p>(1) External stimuli, such as capsaicin, resiniferatoxin or high temperature, activate TRPV1 channels located at the longitudinal SR. (2) TRPV1 channels releases Ca²⁺ from SR to cytoplasm. (3) This low increase in [Ca²⁺]_c activates RyR channels (4) that in return release Ca²⁺ into cytoplasm increasing [Ca²⁺]_c (5). In permanence, SERCA1 pumps continuously back Ca²⁺ from cytoplasm to SR and could mask TRPV1 activation in resting condition.