Pharmacological reagents

All chemicals were purchased from Sigma (USA), except tetrodotoxin (Tocris, Cat. #: 1078), isradipine (Tocris, Cat. #: 2004), pyr3 (Tocris, Cat. #: 2004), ZD-7288 (Tocris, Cat. #: 1000), SKF 96365 (Tocris, Cat. #: 1147), 2-APB (Tocris, Cat. #: 1224), CPP (Tocris, Cat. #: 0247), NBQX (Tocris, Cat. #: 1044), SR 95531 (Tocris, Cat. #: 1262), and CGP-55845 (Tocris, Cat. #: 1248), pyr10 (Millipore, USA, Cat. #: 648494), Fluo-4, OGB-1, and Alexa-594 (Thermo Fisher, USA). Drug stock solutions were prepared in DMSO or deionized water, and stocks were diluted to final concentrations in external solutions via sonication for 10 min.