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Updated: Jun 22, 2026

Dual Somatic Recordings from Gonadotropin-Releasing Hormone (GnRH) Neurons Identified by Green Fluorescent Protein (GFP) in Hypothalamic Slices
Published on: February 23, 2010
Dynorphin immunoreactive fibers contact GnRH neurons in the human hypothalamus
Stephanie K Dahl1, Marcel Amstalden, Lique Coolen
1Department of Obstetrics and Gynecology, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA. stephanie.dahl@meritcare.com
Abstract:
Dynorphin, an endogenous opioid peptide, mediates progesterone-negative feedback on gonadotropin-releasing hormone (GnRH) neurons in other species. The role of dynorphin in humans is unclear. The objective of this study was to determine if dynorphin fibers have close contacts with GnRH neurons in humans. Dual-label immunocytochemistry was performed on postmortem human hypothalamic tissue. The majority of GnRH neurons, 87.5%, had close contacts with dynorphin fibers and multiple close contacts were common, 62.5%. There were no regional differences between the hypothalamus and preoptic area in the distribution of close contacts. More close contacts were identified on the GnRH dendrites compared to the cell bodies (P < .001), but this difference was not significant when corrected for length. In conclusion, dynorphin fibers form close contacts with GnRH neurons in humans. This neuroanatomical evidence may suggest that dynorphin has effects on GnRH regulation in humans as seen in other species.
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