Gaseous transmitters and neuroendocrine regulation

Area of Science:

• Neuroscience
• Endocrinology
• Biochemistry

Background:

• The brain synthesizes significant amounts of nitric oxide (NO) and carbon monoxide (CO).
• Growing evidence suggests these gases function as novel neural messengers.
• Their role in the neuroendocrine axis is increasingly recognized.

Purpose of the Study:

• To review the literature on the role of NO and CO as neurotransmitters and biological mediators in the neuroendocrine axis.
• To explore the involvement of NO and CO in the regulation of reproduction and the hypothalamic-pituitary-adrenal (HPA) axis.
• To discuss their potential roles in controlling other pituitary hormone secretions.

Main Methods:

• Literature review of studies investigating NO and CO in neuroendocrine functions.
• Analysis of evidence for NO's role in gonadotropin-releasing hormone (GnRH) secretion and the luteinizing hormone (LH) surge.
• Examination of studies on CO's effects on GnRH secretion and the HPA axis.

Main Results:

• NO potently stimulates GnRH secretion and mediates glutamate's action, influencing reproduction.
• NO plays a physiological role in the preovulatory LH surge.
• NO restrains the HPA axis, inhibiting stress responses and corticosteroid release.
• CO also appears to stimulate GnRH secretion and restrain the HPA axis.

Conclusions:

• NO and CO act as novel diffusible gas transmitters in the neuroendocrine axis.
• These gases mediate critical neuroendocrine functions, including reproductive control and stress modulation.
• Further research is warranted to fully elucidate their complex roles.