[³H]‐idazoxan binds with high affinity to two sites on hamster adipocytes: an α₂‐adrenoceptor and a non‐adrenoceptor site

α2‐Adrenoceptor subtypes and imidazoline‐like binding sites in the rat brain

“…These studies were carried out using a Na'/K' buffer system. A possible explanation which could account for the large percentage of [3H]-idazoxan binding reported by , is that, under the conditions used, [3H]-idazoxan binds preferentially to a proposed imidazoline-like site, similar to that reported to exist in rabbit adipocytes (Langin & Lafontan, 1989), rabbit urethral tissue (Yablonsky et al, 1988;Yablonsky & Dausse, 1989) and hamster adipocytes (MacKinnon et al, 1989). The low affinity of clonidine and p-aminoclonidine at the imidazoline-like binding sites in rat cerebral cortex indicates that this site is distinct from the imidazoline-like site labelled by [3H]-clonidine and [3H]-p-aminoclonidine in human, rat and bovine brain stem (Ernsberger et al, 1987;Bricca et al, 1988;.…”

The pharmacology of RS‐15385‐197, a potent and selective α2‐adrenoceptor antagonist

“…Hamster adipocyte membranes were prepared as previously described (MacKinnon et al, 1989). White adipose tissue taken from male Syrian hamsters (100-150 g) was finely chopped and suspended in Krebs-Ringer bicarbonate buffer (3 ml g-' tissue) containing 1 mg ml-' collagenase (Sigma type 1) and 3.5% w/v fatty acid free bovine serum albumin.…”

“…et al., 1988;MacKinnon et al, 1989;Michel et al, 1989;Brown et al, 1990a). Yohimbine has been shown to cause a variety of effects in man, such as anxiety and increases in blood pressure and heart rate ), but it is not clear whether all of these effects arise from antagonism of ongoing activation of a2-adrenoceptors.…”

Species‐selective binding of [3H]‐idazoxan to α2‐adrenoceptors and non‐adrenoceptor, imidazoline binding sites in the central nervous system

“…More recently it has been recognized that [3H]-idazoxan also binds to non-adrenoceptor, imidazoline binding sites, which have been identified in the rat cerebral cortex (Brown et al, 1990), guinea-pig cerebral cortex (Wikberg & Uhlen, 1990), rabbit kidney (Lachaurd et al, 1986), hamster adipocytes (MacKinnon et al, 1989) and rabbit urethral smooth muscle (Yablonsky et al, 1988). Pharmacologically these sites are characterized by a high affinity for idazoxan and the imidazoline derivative cirazoline, but low affinity for the endogenous catecholamines, noradrenaline and adrenaline.…”