CS and migraine disorder: It was found that both PACAP-38 (pituitary adenylate cyclase-activating polypeptide-38) and PACAP (6–38) treatment resulted in significant downregulation of complex I subunit B6 expression in primary cultured trigeminal ganglion cells (Takács-Lovász et al., 2022), and metabolic changes and mitochondrial dysfunction, such as reduced complex I, III, IV and citrate synthase activities, were detected in migraine patients (Gross et al., 2019).