Single unit components of the hypothalamic multiunit electrical activity associated with the central signal generator that directs the pulsatile secretion of gonadotropic hormones

Hugo Cardenas, Tamás Ördög, Kevin T. O'Byrne, Ernst Knobil

Research output: Contribution to journalArticlepeer-review

38 Scopus citations

Abstract

Vertebrate reproduction is dependent on the operation of a central signal generator that directs the episodic release of gonadotropin-releasing hormone, a neuropeptide that stimulates secretion of the pituitary gonadotropic hormones and, thereby, controls gonadal function. The electrophysiological correlates of this pulse generator are characterized by abrupt increases in hypothalamic multiunit electrical activity (MUA volleys) invariably associated with the initiation of secretory episodes of luteinizing hormone. Using cluster analysis, we extracted single units from the multiunit signals recorded from the mediobasal hypothalamus of four intact and four ovariectomized rhesus monkeys. Of the 40 individual units identified in this manner, 24 increased their frequency with the MUA volleys. The onset and termination of these single-unit bursts occurred coincidently with those of the MUA volleys in both intact and ovariectomized animals, indicating that the longer duration of the MUA volleys characteristic of the gonadectomized animals was due not to the sequential activation of different units but to the longer bursts of the individual cells. Four other units showed decreases in firing rate during the MUA volleys, while the frequency of the remainder did not change. All the examined units were active during the intervals between the volleys of electrical activity. The results indicate that the MUA volleys associated with the activity of the gonadotropin-releasing hormone pulse generator represent the simultaneous increase in firing rate of some individual hypothalamic neurons and the decrease in the frequency of others.

Original languageEnglish (US)
Pages (from-to)9630-9634
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Volume90
Issue number20
DOIs
StatePublished - Oct 15 1993

Keywords

  • Gonadotropin-releasing hormone pulse generator
  • Rhesus monkey
  • Single unit activity
  • Synchronization

ASJC Scopus subject areas

  • General

Fingerprint Dive into the research topics of 'Single unit components of the hypothalamic multiunit electrical activity associated with the central signal generator that directs the pulsatile secretion of gonadotropic hormones'. Together they form a unique fingerprint.

Cite this