title: Behavioral effects of "vehicle" microinjected into the dorsal periaqueductal grey of rats tested in the elevated plus maze.
abstract: To investigate the behavioral effects of different vehicles microinjected into the dorsal periaqueductal grey (DPAG) of male Wistar rats, weighing 200-250 g, tested in the elevated plus maze, animals were implanted with cannulas aimed at this structure. One week after surgery the animals received microinjections into the DPAG of 0.9% (w/v) saline, 10% (v/v) dimethyl sulfoxide (DMSO), 2% (v/v) Tween-80, 10% (v/v) propylene glycol, or synthetic cerebrospinal fluid (CSF). Ten min after the injection (0.5 microliters) the animals (N = 8-13/group) were submitted to the elevated plus maze test. DMSO significantly increased the number of entries into both the open and enclosed arms when compared to 0.9% saline (2.7 +/- 0.8 and 8.7 +/- 1.3 vs 0.8 +/- 0.3 and 5.1 +/- 0.9, respectively. Duncan test, P < 0.05), and tended to increase enclosed arm entries as compared to 2% Tween-80 (8.7 +/- 1.3 vs 5.7 +/- 0.9, Duncan test, P < 0.10). In a second experiment no difference in plus maze exploration was found between 0.9% saline-or sham-injected animals (N = 11-13/group). These results indicate that intra-DPAG injection of some commonly used vehicles such as DMSO, saline or Tween-80 affects the exploratory activity of rats exposed to the elevated plus maze in statistically different manners.
authors.affiliation: Departamento de Farmacologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Brasil.
authors.forename: M G
authors.initials: MG
authors.lastname: Matheus
authors.forename: J C
authors.initials: JC
authors.lastname: de-Lacerda
authors.forename: F S
authors.initials: FS
authors.lastname: Guimarães
mesh_terms: D000818:Animals; D004121:Dimethyl Sulfoxide / Q000494:pharmacology*; D005106:Exploratory Behavior / Q000187:drug effects; D008297:Male; D018782:Maze Learning / Q000187:drug effects*; D008845:Microinjections; D010487:Periaqueductal Gray / Q000187:drug effects*; D014677:Pharmaceutical Vehicles / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar
chemical_list: D014677:Pharmaceutical Vehicles; D004121:Dimethyl Sulfoxide