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A GABA-neuropeptide Y (NPY) interplay in LH release
1Department of Obstetrics and Gynecology, Yale University School of Medicine, New Haven, Connecticut, USA.
Peptides
|April 5, 2001
Summary
Neuropeptide Y (NPY) stimulates LH release, while GABA inhibits it. Co-released GABA may restrain NPY
Area of Science:
- Neuroendocrinology
- Neurophysiology
- Hypothalamic-pituitary axis regulation
Background:
- Neuropeptide Y (NPY) is known to stimulate luteinizing hormone (LH) release.
- Gamma-amino butyric acid (GABA) is known to inhibit LH release.
- NPY-producing neurons in the arcuate nucleus (ARC) co-express GABA, suggesting a potential interplay.
Purpose of the Study:
- To investigate the interplay between NPY and GABA in regulating LH release.
- To determine if co-released GABA modulates the excitatory effects of NPY on LH release.
Main Methods:
- Light and electron microscopic double staining for NPY and GABA in rat brain sections.
- Intracerebroventricular administration of NPY and muscimol (a GABA(A) receptor agonist) in rats.
- Administration of a selective NPY Y4 receptor agonist (1229U91).
Main Results:
- GABA was detected in NPY-immunoreactive axon terminals in the medial preoptic area (MPOA).
- NPY alone stimulated LH release in steroid-primed rats.
- Muscimol blocked NPY-induced and 1229U91-induced LH release in a dose-dependent manner.
Conclusions:
- GABA is co-localized with NPY in terminals regulating LH release.
- Co-released GABA likely restrains NPY's stimulatory effects on LH release.
- This interaction may be crucial for basal and cyclic LH release in vivo.