The effect of calcium channel antagonists on the aggressive behavior in chronically stressed rats

The influence of some calcium channel antagonists (CaChaA): nifedipine (NIF), nimodipine (NIM), nitrendipine (NITR), cinnarizine (CIN), and flunarizine (FLU) on electric footshock-induced aggressive behavior was investigated in chronically stressed rats. It was found that chronic stress (various stressors over 16 days) reduced the number of fighting attacks (by about 50%) without changing the pain reactivity of rats. The CaChaA given in a single dose (5 mg/kg ip) did not influence the intensity of fighting. However, when the same drugs were administered chronically (5 mg/kg/day) for 14 days they counteracted the reduction of fighting attacks induced by chronic stress. Neither chronic stress nor CaChaA in doses used change the exploratory activity of rats in open field. The obtained results indicate the similarity of CaChaA effects to those of antidepressant drugs in the recovery of aggressiveness reduced by chronic stress.