Article date: November 1989
By: Anton D. Michel, Dana N. Loury, Roger L. Whiting in Volume 98, Issue 3, pages 890-897
The α2‐adrenoceptors of rat submaxillary gland, labelled with [3H]‐rauwolscine, were characterized by use of a range of subtype selective ligands and were compared to rabbit spleen α2A‐adrenoceptors and rat kidney α2B‐adrenoceptors.
In rat submaxillary gland, [3H]‐rauwolscine labelled an apparently homogeneous population of binding sites with relatively low affinity (Kd = 11.65 nm) compared to the affinity in rat kidney (Kd = 2.18 nm) and rabbit spleen (Kd = 4.64 nm).
In competition studies using 16 ligands the α2‐adrenoceptors in rat submaxillary gland appeared to differ from both the α2A‐adrenoceptor of rabbit spleen (r = 0.62) and also the α2B‐adrenoceptor of rat kidney (r = 0.28).
The affinity data obtained with benoxathian, imiloxan and WB 4101 indicated the presence of an α2B‐adrenoceptor in rat submaxillary gland. However, data for chlorpromazine, oxymetazoline, spiroxatrine and xylometazoline indicated that submaxillary gland α2‐adrenoceptors were of the α2A subtype. The affinity estimate for prazosin in rat submaxillary gland was intermediate between its affinity at the α2A‐ and α2B‐adrenoceptors while affinity estimates for idazoxan and phentolamine in rat submaxillary gland were greater than those obtained at either the α2A‐ or α2B‐adrenoceptor.
These data indicate that rat submaxillary gland α2‐adrenoceptors differ from the α2A‐ and α2B‐adrenoceptors found in rabbit spleen and rat kidney, respectively.
The α2‐adrenoceptors of rat submaxillary gland, labelled with [3H]‐rauwolscine, were characterized by use of a range of subtype selective ligands and were compared to rabbit spleen α2A‐adrenoceptors and rat kidney α2B‐adrenoceptors.
In rat submaxillary gland, [3H]‐rauwolscine labelled an apparently homogeneous population of binding sites with relatively low affinity (Kd = 11.65 nm) compared to the affinity in rat kidney (Kd = 2.18 nm) and rabbit spleen (Kd = 4.64 nm).
In competition studies using 16 ligands the α2‐adrenoceptors in rat submaxillary gland appeared to differ from both the α2A‐adrenoceptor of rabbit spleen (r = 0.62) and also the α2B‐adrenoceptor of rat kidney (r = 0.28).
The affinity data obtained with benoxathian, imiloxan and WB 4101 indicated the presence of an α2B‐adrenoceptor in rat submaxillary gland. However, data for chlorpromazine, oxymetazoline, spiroxatrine and xylometazoline indicated that submaxillary gland α2‐adrenoceptors were of the α2A subtype. The affinity estimate for prazosin in rat submaxillary gland was intermediate between its affinity at the α2A‐ and α2B‐adrenoceptors while affinity estimates for idazoxan and phentolamine in rat submaxillary gland were greater than those obtained at either the α2A‐ or α2B‐adrenoceptor.
These data indicate that rat submaxillary gland α2‐adrenoceptors differ from the α2A‐ and α2B‐adrenoceptors found in rabbit spleen and rat kidney, respectively.
DOI: 10.1111/j.1476-5381.1989.tb14618.x
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