Relationship between serotonin and norepinephrine levels and the preimplantation embryo development in rat

We have evaluated the impact of chronic administration of clorgyline, a potent monoamine oxidase A inhibitor and a former antidepressant, on the preimplantation embryo development in Wistar rats.

Females were injected intraperitoneally daily for 30 days with saline (control animals, C), or with a low dose of clorgyline (0.1 mg/kg/day, LDC) or with a high dose of clorgyline (1 mg/kg/day, HDC). Embryos were isolated on day 5 of pregnancy and their urine was collected.

The number of embryos per female did not differ between experimental groups and control, but we have recorded a decreased number of embryos in HDC group compared to LDC (p < 0.05). We have found that LDC significantly reduced the presence of healthy embryos and increased the presence of the degenerated embryos (p < 0.001). The administration of the LDC resulted in the lowest cell number in blastocysts (p < 0.01). Concerning monoamines in urine, we have observed significantly increased serotonin levels in HDC group compared to control (p < 0.05) and LDC animals (p < 0.01). Norepinephrine levels in both experimental groups were significantly elevated compared to controls, too (p < 0.001 LDC vs C; p < 0.01 HDC vs C).

We assume that the impaired embryo development recorded in the LDC group after clorgyline administration was a consequence of the higher levels of the norepinephrine. We speculate that lesser negative effect of HDC compared to LDC on the preimplantation embryo development could be the consequence of the lesser norepinephrine levels and/or elevated serotonin levels (Tab. 2, Fig. 2, Ref. 37). Full Text in free PDF www.bmj.sk.