Longitudinal changes in serum catecholamines, dopamine, serotonin, ACTH and cortisol in pregnant Spanish mares.

The research observes sympathetic nervous system (SNS) and hypothalamus-pituitary-adrenal (HPA) axis activation in pregnant Spanish mares over a span of 11 months, which results in fluctuating levels of certain hormones and neurotransmitters related to stress and physiological changes.

Study Overview

• The study primarily investigates systemic physiological changes associated with pregnancy in Spanish mares. These changes are linked to the activation of the sympathetic nervous system (SNS) and the hypothalamus-pituitary-adrenal (HPA) axis in humans, but there has been limited research on mares.
• Researchers conducted these tests by taking venous blood samples monthly from the 31 mares across their 11-month pregnancy period.

Research Findings

• During the first four months of pregnancy, there were increases in adrenaline (AD), dopamine (DOPA) and Adrenocorticotropic hormone (ACTH), whereas serotonin (5-HT) levels decreased. Additionally, no significant changes were observed in the levels of noradrenaline (NAD) and cortisol (CORT).
• The results demonstrated fluctuations with NAD increasing at the eighth month, serotonin at the fifth and seventh months, while DOPA progressively increased between the fifth and eighth months. Meanwhile, the peak for CORT concentration occurred at the fifth month.
• In the final three months of pregnancy, NAD, 5-HT, and DOPA levels decreased, especially in the last month.

Conclusion and Future Direction

• Findings from the research confirmed an activation of the SNS and the HPA axis in pregnant mares during successful pregnancies just as observed in humans
• The researchers call for further studies to determine if similar changes occur in unsuccessful pregnancies, thus providing a comprehensive understanding of the physiological changes in pregnant mares.