Cortical refractoriness to N-methyl-d, l-aspartic acid (NMA) stimulation in the lactating rat: recovery after pup removal and blockade of progesterone receptors

Rula Abbud, Gloria E. Hoffman, M (Susan) Smith

Research output: Contribution to journalArticle

30 Citations (Scopus)

Abstract

We have previously reported that lactating rats, unlike cycling rats, are refractory to N-methyl-d,l-aspartic acid (NMA), but not kainate, in terms of behavioral responses and activation of cFos expression in the neocortex and hippocampus. To study the factors involved in the suppression of cortical activation in lactating rats in response to NMA, we examined the effects of removing either the suckling stimulus and/or progesterone. The degree of cFos expression was used as a marker for cortical activation. Whereas control suckled animals exhibited little or no cFos activation in the piriform cortex in response to NMA, cycling rats showed a high degree of activation. Blockade of the effects of progesterone or removal of the pups for 24 h, resulted in a moderate level of cFos intensity in response to NMA. Total recovery was observed only in animals who had their pups removed for 24 h and the effects of progesterone were blockad. In general, similar results were obtained in the hippocampus except that the total recovery of hippocampal activation took longer than the cortex. Thus, the deficits in cortical activation depend on the presence of both the suckling stimulus and progesterone. However, progesteron alone cannot induced these cortical deficits since pregnant rats showed no deficits in cortical activation in response to NMA when compared to cycling rats. Therefore, the suckling stimulus is required for the inhibition of NMDA-receptor mediated activation of the cortex and hippocampus. The effects of progesterone appear to act synergistically with the effects of suckling.

Original languageEnglish (US)
Pages (from-to)16-23
Number of pages8
JournalBrain Research
Volume604
Issue number1-2
DOIs
StatePublished - Feb 26 1993
Externally publishedYes

Fingerprint

Progesterone Receptors
Aspartic Acid
Progesterone
Hippocampus
Kainic Acid
Neocortex
N-Methyl-D-Aspartate Receptors

Keywords

  • CFos expression
  • Cortical activation
  • Lactation
  • N-Methyl-d,l-aspartic acid
  • N-Methyl-d-aspartate receptor inactivation
  • progesterone

ASJC Scopus subject areas

  • Developmental Biology
  • Molecular Biology
  • Clinical Neurology
  • Neuroscience(all)

Cite this

Cortical refractoriness to N-methyl-d, l-aspartic acid (NMA) stimulation in the lactating rat : recovery after pup removal and blockade of progesterone receptors. / Abbud, Rula; Hoffman, Gloria E.; Smith, M (Susan).

In: Brain Research, Vol. 604, No. 1-2, 26.02.1993, p. 16-23.

Research output: Contribution to journalArticle

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