Norepinephrine measurement in the isolated, blood-perfused papillary muscle of the dog by using ex vivo microdialysis.
Subendocardial interstitial norepinephrine (NE) was measured in the isolated, blood-perfused papillary muscle (PM) preparation of the dog by using ex vivo microdialysis. A microdialysis fiber was inserted into the base of the PM and perfused with Ringer's solution at a rate of 1 microl/min. Dialyzed NE concentrations were measured by high-performance liquid chromatography with an electrical detector. The basal dialyzed NE concentration from the subendocardial interstitium was 1.74+/-0.24 nM (n = 12, mean +/- SE). When the anterior septal artery was occluded for 5 min, the dialyzed NE concentration from the subendocardial interstitium 0-5 min after occlusion increased to 2.90 +/-0.61 nM (n = 12, p<0.05 versus before occlusion). When desmethylimipramine, a neuronal uptake 1 inhibitor, was administered into the anterior septal artery at a rate of 100 nmol/ml for 30 min, dialyzed NE concentration substantially increased from 1.55+/-0.33 to 2.63+/-0.34 nM (n = 3, p<0.05). Likewise, the occlusion-induced increase in dialyzed NE was augmented to 3.75+/-0.90 nM by desmethylimipramine infusion into the anterior septal artery. These observations suggested that the ex vivo microdialysis of the isolated, blood-perfused PM preparation of the dog is a sensitive method for measuring the subendocardial interstitial NE and that coronary artery occlusion increases the subendocardial interstitial NE as early as within 5 min.
Seya
K
K
Department of Pharmacology, Hirosaki University School of Medicine, 5 Zaifu-cho 036-8562, Hirosaki, Japan.
Daitoku
K
K
Motomura
S
S
D000818:Animals; D002851:Chromatography, High Pressure Liquid; D003891:Desipramine / Q000627:therapeutic use; D004285:Dogs; D005260:Female; D008297:Male; D017551:Microdialysis / Q000379:methods*; D017202:Myocardial Ischemia / Q000188:drug therapy / Q000378:metabolism; D015428:Myocardial Reperfusion Injury / Q000188:drug therapy / Q000378:metabolism; D009638:Norepinephrine / Q000378:metabolism*; D010210:Papillary Muscles / Q000378:metabolism*; D010477:Perfusion; D010496:Pericardium / Q000378:metabolism; D013997:Time Factors
D003891:Desipramine; D009638:Norepinephrine