TRPV1 and obesity due to melanocortin 4 receptor deficiency: Recent studies using this approach have found differential capsaicin-induced meningeal blood flow changes in the presence of diet-induced obesity [63] in mice and suggest a role for TRPV1 signaling in the increased prevalence of migraine with obesity (consistent with the increase in capsaicin-induced nociception and photophobia with obesity [64]; a similar finding was also seen with TRPA1 [65]).