Effect of thyroidal motilin on gastric motility and central modulation in rat thyroid / 中华内分泌代谢杂志

ABSTRACT

Objective To research the functional role of thyroidal motilin and the effects of electric excitation of the paraventricular nuclei(PVN) on gastric motility and the levels of motilin in thyroid and plasma.Methods The expression of motilin in rat and human thyroid was detected by immunofluorescence staining.A phase Ⅲ-like contraction was recorded before and after thyroidectomy and after PVN excitation.The changes in concentrations of plasma FT3,FT4 and motilin were determined via radioimmunoassay (RIA).c-Fos expression of PVN after thyroidectomy and motilin expression in thyroid after PVN excitation were observed by immunohistochemical staining.Results There were motilin immunoreactive cells in rat and human thyroid.The phase Ⅲ-like contraction and concentration of motilin in plasma decreased significantly when measured on the second and fourth days after thyroidectomy(2d,P＜0.01 ;4d,P＜0.05).The expression of c-Fos in PVN after thyroidectomy was significantly increased(P＜0.05).An electric excitation of PVN could increase the concentration of motilin in plasma and thyroid and increase corresponding gastric motility in rats (P ＜0.05).The increased phase Ⅲ-like contraction by PVN excitation could be partially inhibited by administration of motilin receptor antagonist,GM-109 (P＜0.05).Excitation of PVN in thyroidectomized rats resulted in lower plasma motilin and less intense phase Ⅲ-like contraction of stomach,as compared with the sham operated control group(P＜0.05).Conclusion Motilin from the thyroid may be secreted into the peripheral plasma to affect gastric motility and PVN may modulate gastric motility and motilin expression in the thyroid.