Differential behavioral outcomes of 3,4-methylenedioxymethamphetamine (MDMA-ecstasy) in anxiety-like responses in mice

Anxiolytic and anxiogenic-like behavioral outcomes have been reported for methylenedioxymethamphetamine (MDMA or ecstasy) in rodents. In the present experiment, we attempted to identify behavioral, hormonal and neurochemical outcomes of MDMA treatment to clarify its effects on anxiety-related responses in 2-month-old Balb/c male mice (25-35 g; N = 7-10 mice/group). The behavioral tests used were open field, elevated plus maze, hole board, and defensive behavior against predator odor. Moreover, we also determined striatal dopamine and dopamine turnover, and serum corticosterone levels. MDMA was injected ip at 0.2, 1.0, 5.0, 8.0, 10, or 20 mg/kg. MDMA at 10 mg/kg induced the following significant (P < 0.05) effects: a) a dose-dependent increase in the distance traveled and in the time spent moving in the open field; b) decreased exploratory activity in the hole board as measured by number of head dips and time spent in head dipping; c) increased number of open arm entries and increased time spent in open arm exploration in the elevated plus maze; d) increased time spent away from an aversive stimulus and decreased number of risk assessments in an aversive odor chamber; e) increased serum corticosterone levels, and f) increased striatal dopamine level and turnover. Taken together, these data suggest an anxiogenic-like effect of acute MDMA treatment, despite the fact that behavioral anxiety expression was impaired in some of the behavioral tests used as a consequence of the motor stimulating effects of MDMA.

Differential behavioral outcomes of 3,4-methylenedioxymethamphetamine (MDMA-ecstasy) in anxiety-like responses in mice.

Anxiolytic and anxiogenic-like behavioral outcomes have been reported for methylenedioxymethamphetamine (MDMA or ecstasy) in rodents. In the present experiment, we attempted to identify behavioral, hormonal and neurochemical outcomes of MDMA treatment to clarify its effects on anxiety-related responses in 2-month-old Balb/c male mice (25-35 g; N = 7-10 mice/group). The behavioral tests used were open field, elevated plus maze, hole board, and defensive behavior against predator odor. Moreover, we also determined striatal dopamine and dopamine turnover, and serum corticosterone levels. MDMA was injected ip at 0.2, 1.0, 5.0, 8.0, 10, or 20 mg/kg. MDMA at 10 mg/kg induced the following significant (P < 0.05) effects: a) a dose-dependent increase in the distance traveled and in the time spent moving in the open field; b) decreased exploratory activity in the hole board as measured by number of head dips and time spent in head dipping; c) increased number of open arm entries and increased time spent in open arm exploration in the elevated plus maze; d) increased time spent away from an aversive stimulus and decreased number of risk assessments in an aversive odor chamber; e) increased serum corticosterone levels, and f) increased striatal dopamine level and turnover. Taken together, these data suggest an anxiogenic-like effect of acute MDMA treatment, despite the fact that behavioral anxiety expression was impaired in some of the behavioral tests used as a consequence of the motor stimulating effects of MDMA.

Neuroendocrine, behavioral and macrophage activity changes induced by picrotoxin effects in mice.

The relevance and property of studies related to stress effects on immune function are undisputable. All studies conducted on stress-immune relationships, however, provide from physical and/or psychological stressors. Indeed, as far as it is of our knowledge brain-innate immune responses were not analyzed after anxiogenic-like drugs use. The present experiment was then undertaken to analyze the effects of picrotoxin (0.3, 0.6 and 1.0mg/kg doses) on behavior, macrophage activity, serum corticosterone and noradrenaline (NE) levels and turnover in the brain of adult mice. Results showed that picrotoxin treatment in mice: (1) decreased motor and rearing activities in an open-field; (2) decreased the number of entries into the plus-maze open-arms and decreased the time spent in the exploration of the plus-maze open-arms; (3) decreased both motor activity and the level of holes exploration in the hole-board; (4) increased the levels of serum corticosterone in dose-dependent way; (5) increased noradrenaline (NE) and MHPG levels and NE turnover in the hypothalamus; and (6) increased Staphylococcus aureus and PMA-induced macrophage oxidative burst. However, and contrary to that reported after physical or psychological stress, this drug induced no effects on macrophage phagocytosis and NE levels and turnover in the frontal cortex. The present results are thus showing that picrotoxin induces some but not all neuro-innate immunity changes previously reported for inescapable foot-shock and psychological stressors in mice. These facts suggest that this chemical stressor triggers CNS pathways that might be somehow different from those fired by inescapable foot-shock and psychological stressors, leading to different neuro-innate immune responses.