High doses of dopamine reduce sperm motility and acrosomal integrity without affecting the sperm viability over time.

<p><b>A)</b> Effect of dopamine on sperm viability at 1, 3 and 6 hours of incubation. Equine sperm were incubated at 37°C with different concentrations of dopamine (0, 0.01, 0.1 and 1 mM) in Withenn’s buffer and the quantity of viability sperm was calculated using a CASA system, with a minimum of 500 sperm analyzed per experiment. Sperm viability at different times of analysis was normalized to time zero of the control. Results are the mean ± SEM of four independent experiments. <b>B)</b> Effect of dopamine on acrosomal integrity after 1, 3 and 6 hours of incubation. Equine sperm were incubated at 37°C with different dopamine concentrations (0, 0.01, 0.1 and 1 mM) in Withenn’s buffer (enrichment with BSA and bicarbonate) and the percentage of sperms with intact acrosomes was assessed with PSA-FITC staining and by cell count under an epifluorescence microscope. A minimum of 200 sperm were counted. The percentage of intact acrosomes was normalized to time zero of the control without dopamine. Results are the mean ± SEM of four independent experiments. *p<0.05 with respect to the control. <b>C)</b> Effect of dopamine on total sperm motility after incubation for 1, 3 and 6 hours. Equine sperm were incubated at 37°C with different concentrations of dopamine (0, 0.01, 0.1 and 1 mM) in Withenn’s buffer and the quantity of mobile sperm was calculated using a CASA system. A minimum of 500 sperm were analyzed per experiment. Total motility at different times of analysis was normalized to time zero of the control. Results are the mean ± SEM of four independent experiments. **p<0.01 with respect to the control.