Adrenoceptors in the control of human nasal mucosal blood flow.

The blood flow in the human nasal mucosa is controlled by the functional state of the resistance vessels. This blood flow was studied by means of the 133Xe washout method. Using topical application of drugs that stimulate or block adrenoceptors, including clinical doses of nasal decongestants, we classified the adrenoceptors of the resistance vessels in the mucosa. The results suggest that stimulation of alpha2-adrenoceptors causes a reduction of nasal mucosal blood flow; stimulation of alpha1- and beta2-adrenoceptors seems to have no significant effects. Drugs that selectively stimulate alpha2-adrenoceptors, as well as those with preference for alpha1-adrenoceptors, cause nasal decongestion. To avoid the negative effects of a nasal mucosal blood flow reduction, it is suggested that a nasal decongestant with an alpha1-adrenoceptor stimulating effect should be preferable to a drug acting mainly on alpha2-adrenoceptors, provided that the decongestive effects are equal.