| Co-Investigator(Kenkyū-buntansha) |
MIFUNE Hiroharu Institute of Animal Experiment, Kurume University, Assistant Professor, 動物実験センター, 講師 (70174117)
KAWAMINAMI Mitsumori Department of Veterinary Physiology, Kitasato University, Assosiate Professor, 獣医畜産学部, 助教授 (00153007)
|
|---|
| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 1998: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1997: ¥2,800,000 (Direct Cost: ¥2,800,000)
|
|---|
| Research Abstract |
A-type (atrial) natriuretic peptide (ANP) and endothelin have been reported to play essential roles in the control of local circulation of the heart. Annexin V has been reported to be expressed in the heart, however, the functional significance between these peptides and annexin V still remains unknown. We examined the localization of annexin V immunohistochemically, compared them to those of annexins II and VI, and revealed their localization both in the cardiomyocytes and non-myocytes. Then, we observed the heart of fetal and neonatal rats by Western blotting and immunohistochemistry, and showed all of annexins II, V.and VI became detectable at 14 to 16 days in gestation, and annexin V was the first one to become detectable among them. Furthermore, we aimed to examine whether annexin V is associated with the secretion of ANP and endothelin. Atrial cardiocytes were dissociated from neonatal rats and processed for the primary-culture. The cultured cells were divided into 2 groups as follows : (Group 1) Human recombinant annexin V (rAxV) at 0.001 to 1 mum/ml were administrated in the culture medium ; (Group 2) Anti-endothelin antiserum or cytosine 13-D arabino furanoside were applied to the medium to block the function of endothelin, or to prevent the proliferation of non-myocytes respectively, prior to the administration of rAxV.In both groups, the amounts of ANP secreted were measured by radioimrnunoassay at 0 to 48 hr after the administration of rAxV.The administration of rAxV increased the secretion of ANP dose-dependently in group 1. Tn group 2, however, the administration of rAxV caused no change in the amount of ANP.These results suggest that annexin V is synthesized in the myocytes and/or in non-myocytes, secreted into extracellular space, and increases the synthesis and secretion of ANP from the myocytes under the influence of endothelin by autocrine or paracrine manner.
|
