title: Two mechanisms of 3H-catecholamine accumulation in rabbit aorta media differentiated by sensitivity to temperature and corticosterone.
abstract: To characterize the extraneuronal accumulation of catecholamines (CA) in the media of rabbit aorta pieces of isolated media were incubated with 3H-CA (norepinephrine, isoproterenol or normetanephrine) plus 14C-sorbitol (to estimate the extracellular space) for varying periods at 37 or 0 degree C. The 3H-CA accumulation was 1.3 ml/g at 0 degree C and 2.2 ml/g at 37 degrees C. The sorbitol space was 0.6 ml/g at both temperatures. CA accumulation at 0 and 37 degrees C is significantly different from each other and from sorbitol accumulation. Corticosterone and phenoxybenzamine inhibit the temperature-sensitive component of CA accumulation. Accumulation of norepinephrine at 0 degree C is unaffected by corticosterone, phenoxybenzamine or oxytetracycline. The initial rate of NE accumulation at 37 degrees C, from steady state accumulation at 0 degree C, and the initial rate of accumulation at 0 degree C were linear functions of NE concentration between 10(-7) and 10(-2) M. Based on differences in sensitivity to corticosterone and temperature, we conclude that CA accumulation at 0 degree C is different from the accumulation at 37 degrees C.
mesh_terms: D000818:Animals; D002395:Catecholamines / Q000378:metabolism*; D003345:Corticosterone / Q000494:pharmacology*; D005260:Female; D066298:In Vitro Techniques; D007700:Kinetics; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism*; D010118:Oxytetracycline / Q000494:pharmacology; D010293:Pargyline / Q000494:pharmacology; D011427:Propiophenones / Q000494:pharmacology; D011817:Rabbits; D013012:Sorbitol / Q000378:metabolism*; D013696:Temperature
chemical_list: D002395:Catecholamines; D011427:Propiophenones; D013012:Sorbitol; C006104:U 0521; D010293:Pargyline; D003345:Corticosterone; D010118:Oxytetracycline