Regulatory peptides
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Regulatory peptides · May 2004
Effects of angiotensin and vasopressin V(1) receptors on water and sodium intake induced by injection of vasopressin into lateral septal area.
The specific arginine(8)-vasopressin (AVP) V(1) receptors antagonist (AAVP) was injected (20, 40 and 80 nmol) into the lateral septal area (LSA) to determine the effects of selective septal V(1) receptor on water and 3% sodium intake in rats. Was also observed the effects of losartan and CGP42112A (select ligands of the AT(1) and AT(2) ANG II receptors, respectively) injected into LSA prior AVP on the same appetites. Twenty-four hours before the experiments, the rats were deprived of water. ⋯ Losartan and CGP42112A together increased the actions of AVP, showing more pronounced effects than when the two antagonists were injected alone. The results showed that AVP inhibited the appetites and these effects were increased by the AAVP. The involvement of angiotensinergic receptors in the effects of AVP is also suggested.
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Regulatory peptides · May 2004
Relationship between contents of adrenomedullin and distributions of neutral endopeptidase in blood and tissues of rats in septic shock.
Adrenomedullin (ADM), a multifunction peptide with important roles in regulating cardiovascular homeostasis, has the vasodilatory properties and is of particular interest in the pathophysiology of sepsis. ADM levels in plasma and tissues are regulated by the proteolysis of neutral endopeptidase (NEP), the major enzyme of ADM degradation. We observed the NEP activity in the plasma, the activity and distribution of NEP and its mRNA expression in the tissues of rats in septic shock to study the possible role of NEP in elevating tissue ADM concentration during sepsis. ⋯ Plasma NEP activity, tissue NEP activity and its protein and mRNA expression in the left ventricle, aorta, jejunum and lung in the late phase of shock (LS) rats were lower than those in ES and the control, but no statistical change of NEP activity in the kidney was observed. The level of ADM was inversely correlated with NEP activity in the plasma, ventricle and aorta and positively correlated with NEP activity in the jejunum. Thus, in sepsis, the local concentration and action of ADM in tissues may be differentially regulated by NEP.