A new in vitro method of decongestant assay of nasal mucosa: a preliminary report.

BACKGROUND

The calculation of cell planar surface area, successfully used for glomerular mesangial cell-altered contractility, also is a reasonable methodology to assess nasal mucosal contractility. A simple technique that works particularly well with vasoconstriction-inducing agents has been introduced to test the effects of several drugs on patient turbinate nasal mucosa in vitro. This report will introduce this technique and present some of the initial findings.

METHODS

We tested epinephrine, norepinephrine, pseudoephedrine HCl, and methoxamine, respectively, for effectiveness as a vasoconstricting drug. We also tested the effectiveness of verapamil as a vasodilating drug. A piece of nasal mucosa approximately 3 x 4 mm in size was mounted with a 27-gauge needle and submersed in a 4-mL muscle bath in a Petri dish at room temperature. The bath consisted of 4 mL of Kreb's solution. We recorded the decrease of nasal mucosa planar surface area in response to the application of vasoconstricting agents, as measured using a digital microscope connected to a Pentium III with morphometric software, as the estimated degree of contraction. A photograph of the same mucosa was taken every 3 minutes for a total period of 18 minutes.

RESULTS

Nasal mucosa that was mounted in a muscle bath in a Petri dish and treated with a small dose of a nasal decongestant was l observed to contract. Drug dosage determined the degree of nasal mucosa contraction. Nasal mucosa similarly prepared but treated with a vasodilating agent, such as verapamil, exhibited a relaxation response only when pretreated with a vasoconstricting agent, such as methoxamine. Both vasoconstricting and vasodilating drugs induce dose-related responses in planar surface calculation.

CONCLUSION

In this study, drug dosage determined the degree of nasal mucosa contraction. We also found that the rate of contraction and percent of contraction were dose dependent. We believe this new method will prove useful in studying the effects of drugs on nasal blood vessels.