Comparison of norepinephrine responsiveness of mucosal veins in vivo with that of isolated mucosal tissue in vitro in guinea pig nasal mucosa.

ABSTRACT

BACKGROUND: The vascular responsiveness of nasal mucosa has been determined frequently by using isolated mucosal tissues although it is not clear whether the response of the whole tissue truly reflects the response of the vasculature (especially veins) in mucosa. In this study, the in vivo responsiveness of mucosal veins was compared with in vitro responsiveness of isolated mucosal tissue in guinea pig nasal septa. METHODS: The in vivo venous responsiveness to norepinephrine (NE) of guinea pig nasal septal mucosa was measured by changes in the diameters of mucosal veins, stereomicroscopically. The in vitro responsiveness to NE of isolated nasal septal mucosae from guinea pigs also was determined by standard organ-bath technique. RESULTS: Application of NE induced concentration-dependent contractile responses both in vivo and in vitro with the pD2 (negative logarithm for 50% effective concentration [M] of NE) values of 5.23 +/- 0.29 and 5.00 +/- 0.17, respectively. CONCLUSION: The equal potencies obtained by the in vivo and in vitro experiments suggest that an increase in tension of isolated nasal mucosal tissue might be caused by the contraction of mucosal veins. Both the in vivo and the in vitro methods used in this study might be useful for determining vasoreactivity of nasal mucosa in experimental animals.