The effects of mid-late gestational maternal immune activation in rats on dopamine-related behaviours

Abstract

Prenatal infection is a risk factor for schizophrenia in offspring and is believed to be mediated by maternal immune activation (MIA) in response to an infection. Previous studies in our lab investigating the effect of MIA during mid or late gestation found sensorimotor gating deficits, but only in males, and did not observe changes in drug sensitivity, indicating that these periods of gestation are not the most sensitive with regard to the effects of MIA on the developing dopamine system. Therefore, the current study aims to determine whether MIA at another gestational time-point leads to significant changes to dopamine-related behaviour. Polyinosinic:polycytidylic acid (PolyI:C) was injected to induce MIA in pregnant Wistar rats at gestational day (GD) 14. Control dams were given saline injections. MIA-exposed rats were more sensitive to the locomotor-stimulating effects of the psychomimetic amphetamine, an effect most pronounced in male rats given a high dose (2.5 mg/kg) of amphetamine. MIA exposure did not affect sensorimotor gating or locomotor responsivity to the psychotomimetic MK-801.