IP3R-mediated Ca2+ release is modulated by anandamide in isolated cardiac nuclei

S. Currie, R. Rainbow, M-A. Ewart, S. Kitson, E.H. Pliego, K.A. Kane, J.G. McCarron

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

Cannabinoids (CBs) are known to alter coronary vascular tone and cardiac performance. They also exhibit cardioprotective properties, particularly in their ability to limit the damage produced by ischaemia reperfusion injury. The mechanisms underlying these effects are unknown. Here we investigate the intracellular localisation of CB receptors in the heart and examine whether they may modulate localised nuclear Ca2+ release. In isolated cardiac nuclear preparations, expression of both the inositol 1,4,5-trisphosphate receptor type 2 (IP3R) and CB receptors (CB1R and CB2R) was demonstrated by immunoblotting. Both receptors localised to the nucleus and purity of the nuclear preparations was confirmed by co-expression of the nuclear marker protein nucleolin but absence of cytoplasmic actin. To measure effects of IP3R and CBR agonists on nuclear Ca2+ release, isolated nuclei were loaded with Fluo5N-AM. This dye accumulates in the nuclear envelope. Isolated nuclei responded to IP3 with rapid and transient Ca2+ release from the nuclear envelope. Anandamide inhibited this IP3-mediated release. Preincubation of nuclear preparations with either the CB1R antagonist (AM251) or the CB2R antagonist (AM630) reversed anandamide-mediated inhibition to 80% and 60% of control values respectively. When nuclei were pre-treated with both CBR antagonists, anandamide-mediated inhibition of IP3-induced Ca2+ release was completely reversed. These results are the first to demonstrate the existence of cardiac nuclear CB receptors. They are also the first to show that anandamide can negatively modulate IP3-mediated nuclear Ca2+ release. As such, this provides evidence for a novel key mechanism underlying the action of CBs and CBRs in the heart.
LanguageEnglish
Pages804-811
Number of pages8
JournalJournal of Molecular and Cellular Cardiology
Volume45
Issue number6
DOIs
Publication statusPublished - 22 Jul 2008

Fingerprint

Cannabinoid Receptors
Cannabinoids
Nuclear Envelope
Inositol 1,4,5-Trisphosphate Receptors
Cytoplasmic and Nuclear Receptors
Nuclear Proteins
Reperfusion Injury
Immunoblotting
Blood Vessels
Actins
Coloring Agents
anandamide

Keywords

  • inositol trisphosphate receptor
  • cannabinoid receptors
  • nuclear
  • cardiac
  • calcium release

Cite this

Currie, S. ; Rainbow, R. ; Ewart, M-A. ; Kitson, S. ; Pliego, E.H. ; Kane, K.A. ; McCarron, J.G. / IP3R-mediated Ca2+ release is modulated by anandamide in isolated cardiac nuclei. In: Journal of Molecular and Cellular Cardiology. 2008 ; Vol. 45, No. 6. pp. 804-811.
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abstract = "Cannabinoids (CBs) are known to alter coronary vascular tone and cardiac performance. They also exhibit cardioprotective properties, particularly in their ability to limit the damage produced by ischaemia reperfusion injury. The mechanisms underlying these effects are unknown. Here we investigate the intracellular localisation of CB receptors in the heart and examine whether they may modulate localised nuclear Ca2+ release. In isolated cardiac nuclear preparations, expression of both the inositol 1,4,5-trisphosphate receptor type 2 (IP3R) and CB receptors (CB1R and CB2R) was demonstrated by immunoblotting. Both receptors localised to the nucleus and purity of the nuclear preparations was confirmed by co-expression of the nuclear marker protein nucleolin but absence of cytoplasmic actin. To measure effects of IP3R and CBR agonists on nuclear Ca2+ release, isolated nuclei were loaded with Fluo5N-AM. This dye accumulates in the nuclear envelope. Isolated nuclei responded to IP3 with rapid and transient Ca2+ release from the nuclear envelope. Anandamide inhibited this IP3-mediated release. Preincubation of nuclear preparations with either the CB1R antagonist (AM251) or the CB2R antagonist (AM630) reversed anandamide-mediated inhibition to 80{\%} and 60{\%} of control values respectively. When nuclei were pre-treated with both CBR antagonists, anandamide-mediated inhibition of IP3-induced Ca2+ release was completely reversed. These results are the first to demonstrate the existence of cardiac nuclear CB receptors. They are also the first to show that anandamide can negatively modulate IP3-mediated nuclear Ca2+ release. As such, this provides evidence for a novel key mechanism underlying the action of CBs and CBRs in the heart.",
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IP3R-mediated Ca2+ release is modulated by anandamide in isolated cardiac nuclei. / Currie, S.; Rainbow, R.; Ewart, M-A.; Kitson, S.; Pliego, E.H.; Kane, K.A.; McCarron, J.G.

In: Journal of Molecular and Cellular Cardiology, Vol. 45, No. 6, 22.07.2008, p. 804-811.

Research output: Contribution to journalArticle

TY - JOUR

T1 - IP3R-mediated Ca2+ release is modulated by anandamide in isolated cardiac nuclei

AU - Currie, S.

AU - Rainbow, R.

AU - Ewart, M-A.

AU - Kitson, S.

AU - Pliego, E.H.

AU - Kane, K.A.

AU - McCarron, J.G.

PY - 2008/7/22

Y1 - 2008/7/22

N2 - Cannabinoids (CBs) are known to alter coronary vascular tone and cardiac performance. They also exhibit cardioprotective properties, particularly in their ability to limit the damage produced by ischaemia reperfusion injury. The mechanisms underlying these effects are unknown. Here we investigate the intracellular localisation of CB receptors in the heart and examine whether they may modulate localised nuclear Ca2+ release. In isolated cardiac nuclear preparations, expression of both the inositol 1,4,5-trisphosphate receptor type 2 (IP3R) and CB receptors (CB1R and CB2R) was demonstrated by immunoblotting. Both receptors localised to the nucleus and purity of the nuclear preparations was confirmed by co-expression of the nuclear marker protein nucleolin but absence of cytoplasmic actin. To measure effects of IP3R and CBR agonists on nuclear Ca2+ release, isolated nuclei were loaded with Fluo5N-AM. This dye accumulates in the nuclear envelope. Isolated nuclei responded to IP3 with rapid and transient Ca2+ release from the nuclear envelope. Anandamide inhibited this IP3-mediated release. Preincubation of nuclear preparations with either the CB1R antagonist (AM251) or the CB2R antagonist (AM630) reversed anandamide-mediated inhibition to 80% and 60% of control values respectively. When nuclei were pre-treated with both CBR antagonists, anandamide-mediated inhibition of IP3-induced Ca2+ release was completely reversed. These results are the first to demonstrate the existence of cardiac nuclear CB receptors. They are also the first to show that anandamide can negatively modulate IP3-mediated nuclear Ca2+ release. As such, this provides evidence for a novel key mechanism underlying the action of CBs and CBRs in the heart.

AB - Cannabinoids (CBs) are known to alter coronary vascular tone and cardiac performance. They also exhibit cardioprotective properties, particularly in their ability to limit the damage produced by ischaemia reperfusion injury. The mechanisms underlying these effects are unknown. Here we investigate the intracellular localisation of CB receptors in the heart and examine whether they may modulate localised nuclear Ca2+ release. In isolated cardiac nuclear preparations, expression of both the inositol 1,4,5-trisphosphate receptor type 2 (IP3R) and CB receptors (CB1R and CB2R) was demonstrated by immunoblotting. Both receptors localised to the nucleus and purity of the nuclear preparations was confirmed by co-expression of the nuclear marker protein nucleolin but absence of cytoplasmic actin. To measure effects of IP3R and CBR agonists on nuclear Ca2+ release, isolated nuclei were loaded with Fluo5N-AM. This dye accumulates in the nuclear envelope. Isolated nuclei responded to IP3 with rapid and transient Ca2+ release from the nuclear envelope. Anandamide inhibited this IP3-mediated release. Preincubation of nuclear preparations with either the CB1R antagonist (AM251) or the CB2R antagonist (AM630) reversed anandamide-mediated inhibition to 80% and 60% of control values respectively. When nuclei were pre-treated with both CBR antagonists, anandamide-mediated inhibition of IP3-induced Ca2+ release was completely reversed. These results are the first to demonstrate the existence of cardiac nuclear CB receptors. They are also the first to show that anandamide can negatively modulate IP3-mediated nuclear Ca2+ release. As such, this provides evidence for a novel key mechanism underlying the action of CBs and CBRs in the heart.

KW - inositol trisphosphate receptor

KW - cannabinoid receptors

KW - nuclear

KW - cardiac

KW - calcium release

U2 - 10.1016/j.yjmcc.2008.07.005

DO - 10.1016/j.yjmcc.2008.07.005

M3 - Article

VL - 45

SP - 804

EP - 811

JO - Journal of Molecular and Cellular Cardiology

T2 - Journal of Molecular and Cellular Cardiology

JF - Journal of Molecular and Cellular Cardiology

SN - 0022-2828

IS - 6

ER -