Reevaluation of the effect of substance P on nasal salt gland secretion in the duck (Anas platyrhynchos)

Adrenergic and osmoregulatory responses to substance P (SP) were studied in salt-loaded ducks. SP inhibited nasal salt secretion by decreasing the salt concentration of the nasal fluid, but reversed the inhibitory effect of angiotensin II (ANG II) on nasal water and K secretion. SP also stimulated salivation, urinary water excretion, and urinary salt excretion, but diminished the diuretic and saluretic responses to ANG II. The osmoregulatory effects of SP were accompanied by elevated plasma concentrations of norepinephrine and epinephrine. The data suggest that SP may contribute to adrenergic and osmotic regulation in ducks.