Flow diagram of the study designs. (a) In vitro studies, (b) In vivo/ex vivo studies; DIV, day in vitro; OGD, oxygen-glucose deprivation; MTT, 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide; GLUT, glucose transporter; nAChR, nicotinic acetylcholine receptor; e-Cig, electronic cigarettes; LDH, lactate dehydrogenase.