RESUMO
BACKGROUND: Calcitonin gene-related peptide (CGRP) and substance P (SP) play counter-regulatory roles in coronary flow. This study is to assess whether effects of CGRP and SP are gender-specific. METHODS: Langendorff-perfused hearts were used to compare coronary flow rates among 119 wild-type, alpha-CGRP and SP receptor knockout mice under various perfusion pressures (20, 30, 40, 50 mmHg). RESULTS: For mouse heart coronary flow rate, deletion of alpha-CGRP gene resulted in significant reduction for both genders at all pressures; female CGRP knockout showed 15.3% reduction (P < .01); male CGRP knockout showed 13.8% reduction (P < .01); no significant difference between male and female CGRP knockout; female SP receptor knockout showed 13.9% increase (P < .01); female SP receptor knockout had a greater percentage decrease than male (P < .01). CONCLUSIONS: CGRP plays similar roles as a vasodilator in males and females. SP seems to act as a vasoconstrictor in females.
Assuntos
Peptídeo Relacionado com Gene de Calcitonina/metabolismo , Circulação Coronária , Vasos Coronários/metabolismo , Substância P/metabolismo , Vasoconstrição , Vasodilatação , Animais , Velocidade do Fluxo Sanguíneo , Feminino , Técnicas In Vitro , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Modelos Animais , Perfusão , Receptores de Peptídeo Relacionado com o Gene de Calcitonina/deficiência , Receptores de Peptídeo Relacionado com o Gene de Calcitonina/genética , Receptores da Neurocinina-1/deficiência , Receptores da Neurocinina-1/genética , Fatores SexuaisRESUMO
The initially orphan human calcitonin (CT) receptor-like receptor (hCRLR) interacts with novel accessory receptor activity-modifying protein 1 (RAMP1) to reveal a functional CT gene-related peptide (CGRP) receptor. In mammalian cells, RAMP1 is required for mature N-glycosylation of the hCRLR predicted to occur at Asn(60), Asn(112), and/or Asn(117) in the amino-terminal extracellular domain. Here we have shown that the substitution of Asn(117) with Ala, Gln, Thr, or Pro abolished CGRP-evoked cAMP formation which was left unchanged when the Asn(117) was replaced with Asp. Moreover, the hCRLR and the Asn(117) mutants exhibited comparable N-glycosylation and cell surface expression, and the association with RAMP1 was only slightly impaired. In contrast, the hCRLR Asn(60,112) to Thr double mutant exhibited defective RAMP1-dependent N-glycosylation, and impaired cell surface expression and CGRP receptor function. Unlike Asn(60) and Asn(112), Asn(117) is normally not N-glycosylated, but essential for CGRP binding to the hCRLR-RAMP1 complex.
