Interactive effects of prenatal exposure to restraint stress and alcohol on pentylenetetrazol-induced seizure behaviors in rat offspring

Prenatal exposure to stress or alcohol increases vulnerability of brain regions involved in neurobehavioral development and programs susceptibility to seizure. To examine how prenatal alcohol
interferes with stress-sensitive seizures, corticosterone (COS) blood levels and pentylenetetrazol (PTZ)-
induced seizure behaviors were investigated in rat pups, prenatally exposed to stress, alcohol, or both.
Pregnant rats were exposed to stress and saline/alcohol on 17, 18, and 19 days of pregnancy and divided
into four groups of controlesaline (CS), controlealcohol (CA), restraint stressesaline (RS), and restraint
stressealcohol (RA). In CS/CA groups, rats received saline/alcohol (20%, 2 g/kg, intraperitoneally [i.p.]). In
RS/RA groups, rats were exposed to restraint stress by being held immobile in a Plexiglas� tube (twice/
day, 1 h/session), and received saline/alcohol, simultaneously. After parturition, on postnatal days 6 and
15 (P6 & P15), blood samples were collected from the pups to determine COS level. On P15 and P25, PTZ
(45 mg/kg) was injected into the rest of the pups and seizure behaviors were then recorded. COS levels
increased in pups of the RS group but not in pups of the RA group. Both focal and tonic-clonic seizures
were prevalent and severe in pups of the RS group, whereas only focal seizures were prominent in pups
of the CA group. However, pups prenatally exposed to co-administration of alcohol and stress, unexpectedly, did not show additive epileptic effects. The failure of pups prenatally exposed to alcohol to
show progressive or facilitatory epileptic responses to stressors, indicates decreased plasticity and
adaptability, which may negatively affect HPA-axis performance or hippocampal structure/function