Carbamazepine regulates feline aggression elicited from the midbrain periaqueductal gray

Carbamazepine has been utilized both as an anticonvulsant and as a psychotropic drug for the treatment of complex partial seizures and various mood and other emotional disorders such as the episodic dyscontrol syndrome. In the present study, we sought to identify the role of carbamazepine in the regulation of two forms of aggressive behavior--affective defense and quiet biting attack behavior--elicited by electrical stimulation of the midbrain periaqueductal gray matter of the cat in the absence of convulsive activity. The experimental paradigm involved establishment of stable baseline thresholds for affective defense and quiet biting attack responses. Following establishment of a stable baseline, carbamazepine (2.5, 5, or 10 mg/kg) and propylene glycol (vehicle control) were administered peripherally (IP). The response thresholds were tested 5-30, 30-60, 60-90, 120-150, 1440-1470, and 2160-2190 minutes following drug administration. It was observed that carbamazepine administration at 5 and 10 mg/kg dose levels preferentially suppressed affective defense behavior but had no effect upon quiet biting attack, indicating that the selective effects of carbamazepine upon affective attack are not due to any possible sedative effects upon motor responses. The effects of carbamazepine upon affective defense were dose dependent and of long duration when administered at the highest dose level (10 mg/kg).