Effects of Acute Swimming Stress on the Behavioral and Neurochemical Effects of Pyrazolo[C]pyridine Derivative GIZh-72 and Diazepam in BALB/c and C57BL/6 Mice

The effects of acute swimming stress (ASS) on the behavioral and neurochemical actions of a pyrazolo[C]pyridine derivative GIZh-72 (20 mg/kg, i.p.) and diazepam (1 mg/kg, i.p.) were studied. Increased anxiety reactions were seen in the open field test 1 h after ASS in BALB/c mice and the marble burying test in C57BL/6 mice. Weakening of anxiety reactions in BALB/c and C57BL/6 mice in the open field test and in C57BL/6 mice in the marble burying test was noted at 24 h. Serotonin levels increased and noradrenaline levels decreased in the hypothalamus of BALB/c and C57BL/6 mice 1 h after ASS, while the prefrontal cortex showed increases in noradrenaline, 3,4-dihydroxyphenylacetic acid, and the 3,4-dihydroxyphenylacetic acid/dopamine ratio in BALB/c mice. These changes correlated with increases in anxiety reactions, while their reversal in response to GIZh-72 and diazepam or 24 h after ASS coincided with weakening of anxiety reactions in mice. Diazepam and GIZh-72 weakened anxiety reactions in BALB/c and C57BL/6 mice in the open field and marble burying tests in the absence of stress. At 1 h after ASS, the effects of GIZh-72 were retained in BALB/c and C57BL/6 mice in the open field and marble burying tests, while the effects of diazepam persisted in C57BL/6 mice and increased in BALB/c mice in the open field test. At 24 h, the effects of GIZh-72 in the open field test increased in BALB/c mice but weakened and were accompanied by a tendency to a sedative action in C57BL/6 mice. The effects of diazepam in the open field increased only in C57BL/6 mice and were absent in BALB/c mice. The effects of GIZh-72 and diazepam in the marble burying test 2 h after ASS persisted in BALB/c but not C57BL/6 mice.