Effects of haloperidol on behavioral responses induced by electrical stimulation of medial prefrontal cortex

The effects of haloperidol on circling and spying behaviors induced by electrical stimulation of the medial prefrontal cortex (PFC) were evaluated. Male Wistar rats with an electrode implanted into the left medial PFC (B: 2.5 mm A, 0.6 mm L and 2.7 mm V) were electrically stimulated in a sequence of ten 30-sec trains separated by 30-sec intervals (60 Hz) in each session, and simultaneously observed in the open field. The animals with circling (CI) and spying (SP) behaviors were treated with intraperitoneal haloperidol (HAL ip, 5 mg/kg, N = 6) and saline (SAL ip, N = 7) or intracortical HAL (ic, 5 micrograms, N = 6) and SAL (ic, N = 9), 20 min before the session of electrical stimulation. HAL ic significantly decreased (P < 0.05) CI (mean frequency +/- SEM: 0.5 +/- 0.16) and nonsignificantly decreased SP behavior (0.6 +/- 0.17) compared to SAL ic (CI: 0.9 0.02, SP: 1 +/- 0). HAL ip full abolished these behaviors (P < 0.05) (CI: 0.02 +/- 0, SP: 1 +/- 0) compared to SAL ip (CI: 0.86 +/- 0.06, SP: 0:93 +/- 0.06). These results show that haloperidol, a dopaminergic antagonist and antipsychotic agent, interfered significantly with the expression of behaviors induced by electrical stimulation of the left medial PFC, suggesting that the induction of these behaviors may involve the dopaminergic neurotransmission.