Psychiatry related information on Brl 48553

• Only MDA induced locomotor activity when given alone, but in the presence of BRL 44408, MDMA produced increased locomotor activity [1].

High impact information on Brl 48553

• Rats underwent partial ligation of one sciatic nerve, and peri-neural saline, clonidine or a combination of clonidine and the alpha2A-adrenceptor-preferring antagonist, BRL44408, were administered before wound closure and, in some animals, also 24 and 48 h later [2].
• In the porcine ciliary arteries BRL44408, ARC239, and prazosin caused concentration-dependent and parallel rightward shifts of the concentration-response curves for brimonidine [3].
• In MAO-A KO mice, BRL 44408 (100 nm) increased evoked NA efflux on short trains while ARC 239 (100 nm) had no effect [4].
• At 37 degrees C, alpha(2)-AR-induced vasoconstriction in distal arteries was inhibited by selective blockade of alpha(2A)-ARs (BRL-44408) but not by selective inhibition of alpha(2B)-ARs (ARC-239) or alpha(2C)-ARs (MK-912) [5].
• The selective alpha(2)- versus alpha(1)-AR antagonists, atipamezole and BRL-44408 (a preferential alpha(2A)-AR antagonist), elevated levels of NE and DA but not 5-HT [6].

Biological context of Brl 48553

• Alternative incubation in the presence of ARC 239 (50 nM) to mask alpha 2B-adrenoceptors or BRL 44408 (100 nM) to mask alpha 2D-adrenoceptors confirmed the existence of both alpha 2-adrenoceptor subtypes and a non-adrenoceptor imidazoline binding site [7].
• The rank order of potency of antagonists in preventing dexmedetomidine- and oxymetazoline-evoked suppression of isoprenaline-induced lipolysis was (pA2-values): CH-38083 (7.69 and 7.48) congruent to idazoxan (7.5 and 7.41) > BRL44408 (7.23 and 7.19) congruent to WB4101 (7.13 and 7.12) > prazosin (5.18 and 5.17) > ARC-239 (4.72, 4.9) [8].

Anatomical context of Brl 48553

• 2. The alpha 2B-selective adrenoceptor antagonists, prazosin, ARC 239 and HV 723 showed high, and the alpha 2A-selective antagonist BRL 44408 showed low, potency in human saphenous vein [9].
• In agreement with the data of microdialysis and perfusion experiments, BRL 44408 displaced [3H]yohimbine from hippocampal and cortical membranes of rat brain with high affinity whereas ARC 239 was less effective [10].
• The relatively non-selective alpha2-adrenoceptor antagonist yohimbine and the alpha2D-adrenoceptor selective antagonist BRL 44408 had potencies in rat atrium which were similar to their potencies in rat cerebral cortex [11].
• In contrast, the antagonist BRL 44408 (alpha 2D selective, 1-10 mg/kg) did not increase the synthesis of dopa in cortex, and increased it modestly in hippocampus only [12].
• The alpha 2B-selective adrenoceptor antagonists prazosin and ARC 239 showed significantly higher, and the alpha 2A-selective antagonist BRL 44408 showed significantly lower, potency in atrium than in vas deferens and submandibular gland [13].

Associations of Brl 48553 with other chemical compounds

• The following antagonists were employed (potencies, pKB, in human saphenous vein in parentheses): chlorpromazine (6.98 +/- 0.24), BDF 8933 (7.60 +/- 0.06), prazosin (6.62 +/- 0.15), ARC 239 (7.19 +/- 0.15), yohimbine (7.23 +/- 0.09), HV 723 (7.52 +/- 0.14), WB 4101 (7.90 +/- 0.06), SKF 104078 (6.55 +/- 0.08), BRL 44408 (5.72 +/- 0.21) [14].
• The same rank order was found for the affinities of these compounds for [3H]yohimbine binding in human platelet membranes, containing only alpha 2A-adrenoceptors, but does not correlate with the known affinities for alpha 2B-adrenoceptors (BRL-41992 > or = imiloxan > BRL-44408) [15].

Gene context of Brl 48553

• The results indicate that BRL 44408 and ARC 239 recognize 5-HT1A receptors in addition to alpha 2-adrenoceptors [16].
• Administration of the alpha2A-adrenoceptor antagonist BRL 44408 (1 mg/kg, i.p.) prevented amitriptyline and imipramine antinociception, whereas the alpha2B/C-adrenoceptor antagonist ARC 239 (10 mg/kg, i.p.) was ineffective [17].
• The rank order of apparent EC50 values was BRL 44408 < BRL 41992 < WB-4101, and correlated best with constants for the alpha 2A-C10/alpha 2A adrenoceptor subtype [18].

References