Chronic imipramine treatment sensitizes '5-HT IND 1A'and '5-HT IND 2A'receptors in the dorsal periaqueductal gray matter: evidence from elevated T-maze test of anxiety - Zanoveli, J. M.; Nogueira, R. L.; Zangrossi Júnior, Hélio (Behavioural phermacology, 2005)