![]() ![]() The neuromodulatory role of vasoactive intestinal peptide (VIP) in avian salt gland secretion and blood flow was investigated in conscious saltwater-acclimated Pekin ducks. This action may not necessarily be associated with changes in renal prostaglandin E2 activity. The results suggest that the kallikrein-kinin system may contribute to changes in renal function during extracellular volume expansion. Aprotinin significantly suppressed urinary immunoreactive prostaglandin E2 excretion in non-expanded rats and in volume-expanded rats during the expansion phase, but not during stable expansion.Ħ. Urinary immunoreactive prostaglandin E2 excretion significantly increased during the expansion phase but returned to below the control range during stable extracellular fluid volume expansion.ĥ. ![]() In volume-expanded rats aprotinin significantly reduced GFR, hippuran clearance, urine volume (V) UNaV, UKV and Cwater/GFR without effect on systemic arterial pressure.Ĥ. In noa-expanded rats aprotinin had no effect on arterial pressure, glomerular filtration rate (GFR), hippuran clearance, urinary flow rate, absolute sodium and potassium excretion or free-water clearance.ģ. Aprotinin, a potent kallikrein inhibitor, was given to conscious rats with and without expansion of the extracellular fluid volume with isotonic saline.Ģ. Because dextran increased the intravascular volume while the interstitial fluid volume (ISFV) decreased, we conclude that the th was inversely correlated with ISFV.ġ. When the colloid dextran was added to the control solution, its infusion increased the colloid osmotic pressure of the blood and decreased nasal secretion. The salt and water secreted again equaled the amounts infused, indicating that the threshold concentration of Na+ (th) for salt gland secretion was decreased by the increase in ECF volume. Infusions of control solution followed these experimental infusions. Thus, ECF volume increased and the Na+ concentration decreased. Salt and water secreted in response to experimental infusions of hyposmotic saline or blood were less than the solute and water infused. When a control solution of 1,000 mosmol NaCl/kg H2O was infused intravenously at 0.2, 0.4, or 0.6 ml/min for 60-90 min, the infused loads were secreted in approximately equal quantities, indicating that the amount of NaCl in the extracellular fluid (ECF) before and after each infusion did not change. Pekin ducks were reared and maintained on 620 mosmol NaCl/kg H2O to enhance the secretory capability of their salt glands. ![]()
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