Interactions between hippocampal serotonin and the pituitary-adrenal axis in the septal driving of hippocampal theta-rhythm1

Efrain C. Azmitia, Neil McNaughton, Lila Tsaltas, Marianne Fillenz, Jeffrey A. Gray

Research output: Contribution to journalArticlepeer-review


Stimulation of the septal area at a frequency between 6 and 10 Hz is able to drive hippocampal theta. In freely moving male rats, the minimum threshold current for driving theta occurs at 7.7 Hz. Disruption of the pituitary-adrenal axis by injection of corticosterone to normal rats or by bilateral adrenalectomy (ADX) causes a shift of the minimum theta-driving threshold to 6.9 Hz. Corticosterone injection to ADX rats returns the minimum to 7.7 Hz. Specific and localized removal of hippocampal serotonergic fibers by intracerebral injections of 5,7-dihydroxytryptamine (5,7-DHT) produces the same shift to a 6.9-Hz minimum threshold as does corticosterone or ADX. We further report that these effects of manipulating the adrenocortical and serotonergic systems act through related (or common) mechanisms since: (1) 5,7- DHT shift to 6.9 Hz can be reversed to 7.7 Hz by injection of corticosterone, (2) 5,7-DHT lesions in an ADX rat produce a normal theta threshold minimum at 7.7 Hz. and (3) in a combined ADX- and 5,7-DHT-lesioned rat, corticosterone again produces a 6.9-Hz minimum as this hormone does in normal rats. These results suggest that the serotonergic inputs to the hippocampus interact with the same neurons which concentrate corticosterone.

Original languageEnglish (US)
Pages (from-to)471-475
Number of pages5
Issue number5
StatePublished - 1984


  • 5,7-Dihydroxytryptamine
  • Adrenalectomy
  • Corticosterone
  • Hippocampal theta-rhythm
  • Hippocampus
  • Serotonin

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Endocrinology
  • Endocrine and Autonomic Systems
  • Cellular and Molecular Neuroscience


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