Alpha 2-adrenoceptors in homogenates of rat nasal mucosa.
The specific binding of [3H]rauwolscine to rat nasal mucosa membranes was saturable, stereoselective and of high affinity. The Scatchard plot pointed to a homogeneous population of binding sites (Kd = 3.6 +/- 0.6 nM; Bmax = 5.1 +/- 0.7 pmol/g). The non-specific binding appeared to be non-linear, probably due to filter binding. Inhibition of [3H]rauwolscine binding with the subtype-selective antagonist, prazosin, suggested the presence of alpha 2-adrenoceptor subclasses in rat nasal mucosa. The (-)-epinephrine inhibition curves demonstrated high- and low-affinity agonist binding sites. A monophasic (-)-epinephrine inhibition curve was obtained in the presence of guanine nucleotides.
Van Megen
Y J
YJ
Department of Otorhinolaryngology, University of Nijmegen, The Netherlands.
Rodrigues de Miranda
J F
JF
Klaassen
A B
AB
Wentges
B T
BT
Van Ginneken
C A
CA
D000818:Animals; D003000:Clonidine / Q000494:pharmacology; D004837:Epinephrine / Q000037:antagonists & inhibitors; D006165:Guanylyl Imidodiphosphate / Q000494:pharmacology; D066298:In Vitro Techniques; D007700:Kinetics; D009297:Nasal Mucosa / Q000378:metabolism*; D011224:Prazosin / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011942:Receptors, Adrenergic, alpha / Q000378:metabolism*; D013237:Stereoisomerism; D015016:Yohimbine / Q000378:metabolism / Q000494:pharmacology
D011942:Receptors, Adrenergic, alpha; D015016:Yohimbine; D006165:Guanylyl Imidodiphosphate; D003000:Clonidine; D011224:Prazosin; D004837:Epinephrine