Spectrophotometric determination of cation concentrations in olfactory mucus

Spectrophotometric techniques were used to determine the concentrations of Na+, K+ and Ca2+ in the olfactory mucus of frogs. The mean concentrations in mEq/l were: [Na+], 52.7 +/- 4.1; [K+], 10.6 +/- 1.9 and [Ca2+], 10.7 +/- 1.7. Topical application of the odorant cineole was associated with statistically significant increases in [Na+] and [Ca2+]; the secretagogues methacholine and isoproterenol induced transient increases in [Na+]. Cineole and methacholine caused sustained increases in [Na+]/[K+] from the control value of 5:1, while isoproterenol caused a transient increase followed by a decline. The results indicate that the cation concentrations in olfactory mucus samples are more similar to those derived from secretory tissue than to those found in the extracellular fluids surrounding typical neural tissue.