Lack of presynaptic interaction between glucocorticoid and CB1 cannabinoid receptors in GABA- and glutamatergic terminals in the frontal cortex of laboratory rodents

Rafael M. Bitencourt, A. Alpár, Valentina Cinquina, Samira G. Ferreira, Bárbara S. Pinheiro, Cristina Lemos, Catherine Ledent, Reinaldo N. Takahashi, Fernando J. Sialana, Gert Lubec, Rodrigo A. Cunha, Tibor Harkany, Attila Köfalvi

Research output: Contribution to journalArticle

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Abstract

Corticosteroid and endocannabinoid actions converge on prefrontocortical circuits associated with neuropsychiatric illnesses. Corticosteroids can also modulate forebrain synapses by using endocannabinoid effector systems. Here, we determined whether corticosteroids can modulate transmitter release directly in the frontal cortex and, in doing so, whether they affect presynaptic CB1 cannabinoid receptor- (CB1R) mediated neuromodulation. By Western blotting of purified subcellular fractions of the rat frontal cortex, we found glucocorticoid receptors (GcRs) and CB1Rs enriched in isolated frontocortical nerve terminals (synaptosomes). CB1Rs were predominantly presynaptically located while GcRs showed preference for the post-synaptic fraction. Additional confocal microscopy analysis of cortical and hippocampal regions revealed vesicular GABA transporter-positive and vesicular glutamate transporter 1-positive nerve terminals endowed with CB1R immunoreactivity, apposing GcR-positive post-synaptic compartments. In functional transmitter release assay, corticosteroids, corticosterone (0.1-10 microM) and dexamethasone (0.1-10 microM) did not significantly affect the evoked release of [3H]GABA and [14C]glutamate in superfused synaptosomes, isolated from both rats and mice. In contrast, the synthetic cannabinoid, WIN55212-2 (1 microM) diminished the release of both [3H]GABA and [14C]glutamate, evoked with various depolarization paradigms. This effect of WIN55212-2 was abolished by the CB1R neutral antagonist, O-2050 (1 microM), and was absent in the CB1R KO mice. CB2R-selective agonists did not affect the release of either neurotransmitter. The lack of robust presynaptic neuromodulation by corticosteroids was unchanged upon either CB1R activation or genetic inactivation. Altogether, corticosteroids are unlikely to exert direct non-genomic presynaptic neuromodulation in the frontal cortex, but they may do so indirectly, via the stimulation of trans-synaptic endocannabinoid signaling.

Original languageEnglish
Pages (from-to)72-84
Number of pages13
JournalNeurochemistry International
Volume90
DOIs
Publication statusPublished - Oct 11 2014

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Cannabinoid Receptor CB1
Frontal Lobe
gamma-Aminobutyric Acid
Glucocorticoids
Rodentia
Adrenal Cortex Hormones
Endocannabinoids
Synaptosomes
Glucocorticoid Receptors
Glutamic Acid
Vesicular Glutamate Transport Protein 1
Cannabinoid Receptor Antagonists
Subcellular Fractions
Cannabinoids
Corticosterone
Prosencephalon
Confocal Microscopy
Synapses
Dexamethasone
Neurotransmitter Agents

Keywords

  • CB cannabinoid receptor
  • Frontal cortex
  • GABA
  • Glucocorticoid receptor
  • Glutamate
  • Presynaptic

ASJC Scopus subject areas

  • Cellular and Molecular Neuroscience
  • Cell Biology

Cite this

Lack of presynaptic interaction between glucocorticoid and CB1 cannabinoid receptors in GABA- and glutamatergic terminals in the frontal cortex of laboratory rodents. / Bitencourt, Rafael M.; Alpár, A.; Cinquina, Valentina; Ferreira, Samira G.; Pinheiro, Bárbara S.; Lemos, Cristina; Ledent, Catherine; Takahashi, Reinaldo N.; Sialana, Fernando J.; Lubec, Gert; Cunha, Rodrigo A.; Harkany, Tibor; Köfalvi, Attila.

In: Neurochemistry International, Vol. 90, 11.10.2014, p. 72-84.

Research output: Contribution to journalArticle

Bitencourt, RM, Alpár, A, Cinquina, V, Ferreira, SG, Pinheiro, BS, Lemos, C, Ledent, C, Takahashi, RN, Sialana, FJ, Lubec, G, Cunha, RA, Harkany, T & Köfalvi, A 2014, 'Lack of presynaptic interaction between glucocorticoid and CB1 cannabinoid receptors in GABA- and glutamatergic terminals in the frontal cortex of laboratory rodents', Neurochemistry International, vol. 90, pp. 72-84. https://doi.org/10.1016/j.neuint.2015.07.014
Bitencourt, Rafael M. ; Alpár, A. ; Cinquina, Valentina ; Ferreira, Samira G. ; Pinheiro, Bárbara S. ; Lemos, Cristina ; Ledent, Catherine ; Takahashi, Reinaldo N. ; Sialana, Fernando J. ; Lubec, Gert ; Cunha, Rodrigo A. ; Harkany, Tibor ; Köfalvi, Attila. / Lack of presynaptic interaction between glucocorticoid and CB1 cannabinoid receptors in GABA- and glutamatergic terminals in the frontal cortex of laboratory rodents. In: Neurochemistry International. 2014 ; Vol. 90. pp. 72-84.
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AU - Ferreira, Samira G.

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AU - Lemos, Cristina

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AU - Takahashi, Reinaldo N.

AU - Sialana, Fernando J.

AU - Lubec, Gert

AU - Cunha, Rodrigo A.

AU - Harkany, Tibor

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