Pharmacological Characterization of Postjunctional α-Adrenoceptors in Human Nasal Mucosa

Abstract

Our results indicate that functional alpha1- and alpha2-adrenoceptors are present and functional in human nasal mucosa. The alpha2-adrenoceptors display a predominant role in contracting the veins and the alpha1-adrenoceptors appear to preferentially constrict the human nasal arteries.

Synephrine, a Component of Evodiae Fructus, Constricts Isolated Rat Aorta via Adrenergic and Serotonergic Receptors

“…In the present study undertaken to clarify the mechanism of the constrictive effects of Evodiae Fructus on rat aorta, we focused on the effects of adrenergic and serotonergic receptors on the constrictive effects. It is known that adrenergic α 1 -receptors are related to the constriction of blood vessels (8,9). The constrictive effects of Evodiae Fructus were competitively inhibited by pretreatment with prazosin, an adrenergic α 1 -antagonist, although pretreatment with propranolol, an adrenergic β-antagonist, did not affect the constrictive effects.…”

Pharmacological Characterization of a Novel α2C-Adrenoceptor AgonistN-[3,4-dihydro-4-(1H-imidazol-4-ylmethyl)-2H-1, 4-benzoxazin-6-yl]-N-ethyl-N′-methylurea (Compound A)

“…Indeed, nasal decongestion is triggered by an active constriction of the venous sinusoids (Kristiansen et al, 1993), and a decrease in nasal cavity pressure after ␣-adrenoceptor agonist administration reflects shrinkage of nasal capacitance vessels (Berridge and Roach, 1986). Several other studies in different species (Lacroix, 1989;Corboz et al, 2003Corboz et al, , 2007Corboz et al, , 2008Wang and Lung, 2003), including human (Johannssen et al, 1997;Corboz et al, 2005), indicated a predominance of the ␣ 2 -adrenenoceptor mechanism in the regulation of capacitance vessels. In addition, ␣ 2 -adrenoceptor proteins are expressed in human nasal mucosa (Corboz et al, 2005) and levels of ␣ 2 -adrenoceptor protein are higher than ␣ 1 -adrenoceptor protein in nasal mucosa of nonallergic and allergic patients (van Megen et al, 1991).…”

“…An ␣ 2 -adrenoceptor agonist, by preferentially constricting venous capacitance blood vessels over arterial resistance blood vessels in nasal mucosa (Corboz et al, 2005(Corboz et al, , 2008, should thus avoid the hypertensive liability of ␣ 1 -adrenoceptor agonists. It is known that ␣ 2 -adrenoceptor agonists produce decongestion in humans, and in the 1960s, the ␣ 2 -adrenoceptor agonist clonidine was initially developed for the treatment of nasal congestion (Stahle, 2000), as was Tinazoline (Nagarajan et al, 1981), and more recently, an ␣ 2 -adrenoceptor agonist demonstrated significant relief of nasal congestion in human subjects with allergic rhinitis (Berkowitz et al, 2005).…”

Effects of the inverse alpha‐agonist doxazosin in allergic rhinitis

“…The clinical implication of these findings is that at least in the medium term over [3][4][5] weeks the use of oral alpha blockade does not result in any therapeutic benefit for patients with mild allergic rhinitis in terms of nasal airway patency or symptoms. For such patients who are taking concomitant alpha blockers for the indications of hypertension or prostatic hypertrophy, there appears to be no cogent rationale for stopping treatment.…”