a1 Department of Pharmacology, Vanderbilt. University, Nashville, TN, USA
Animals with the neonatal ventral hippocampal lesion (NVHL) demonstrate altered responsiveness to stress and various drugs reminiscent of that in schizophrenia. Post-pubertal onset of abnormalities suggests the possibility of sex differences in NVHL effects that may model sex differences in schizophrenia. Here we demonstrate that novelty- and MK-801-induced hyperactivity is evident in both male and female NVHL rats, whereas only NVHL males were hyperactive in response to apomorphine. Next, we examined the sex- and NVHL-dependent differences in the activity of the ERK and Akt pathways. The basal activity of both pathways was higher in females than in males. NVHL reduces the level of phosphorylation of ERK1/2, Akt, and GSK-3 in both sexes, although males show more consistent down-regulation. Females had higher levels of G-protein-coupled kinases [G-protein-coupled receptor kinase (GRK)] 3 and 5, whereas the concentrations of other GRKs and arrestins were the same. In the nucleus accumbens, the concentration of GRK5 in females was elevated by NVHL to the male level. The data demonstrate profound sex differences in the expression and activity of signalling molecules that may underlie differential susceptibility to schizophrenia.
(Received December 07 2009)
(Reviewed January 04 2010)
(Revised January 11 2010)
(Accepted January 13 2010)
(Online publication February 17 2010)
c1 Address for correspondence: Dr E. V. Gurevich, Vanderbilt University, Department of Pharmacology, 2200 Pierce Ave, PRB 454, Nashville, TN 37232, USA. Tel.: 615-936-2720 Fax: 615-343-6532 Email: Eugenia.Gurevich@vanderbilt.edu