Intrauterine and lactational exposure to fluoxetine enhances endothelial modulation of aortic contractile response in adult female rats.

The study aimed to evaluate if maternal exposure to fluoxetine (FLX) during pregnancy and lactation would result in altered aortic reactivity in adult offspring. We also sought to understand the role of endothelium derived relaxing factors in aortic response. Wistar rats (75­80 days old), whose progenitors had received FLX (5 mg/kg, FLX offspring) or tap water (control offspring) during pregnancy and lactation were anesthetized, after which the aorta was removed and cut into two rings, one with (Endo+) and the other without (Endo-) endothelium. Concentration-effect curves for acetylcholine (ACh), sodium nitroprusside (SNP), and phenylephrine (Phe) were performed. The vasodilation to ACh and SNP was similar between control and FLX groups in both male and female offspring. In male rats, the response to Phe was similar between the FLX and control groups on Endo+ and Endo- rings. The response to Phe was reduced on Endo+ rings from female FLX when compared with the control group. The endothelium removal, as well as L-NAME, indomethacin, and tranylcypromine incubation corrected the reduced Phe-induced contraction in the aorta from the female FLX group. On the other hand, catalase, NS-398, and L-NIL did not interfere with the vasoconstriction. The aortic level of nitric oxide (NO) was higher in the female FLX than the control group. Although endothelial NO synthase isoform and cyclooxygenase (COX)-1 expressions were similar between the groups, there was a notable increment in neuronal NO synthase expression in the aorta of FLX-exposed female rats, suggesting an important role of this enzyme in the higher levels of NO. Our results show that developmental exposure to FLX causes sex-specific alteration in aortic function through a mechanism involving endothelial factors, probably NO and COX-1 products.