Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:4.6.1.1 (adenylate cyclase)
 19,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Although hypothermic cardioplegic arrest is a basic method of myocardial protection in cardiac surgery, the beta-adrenergic receptor (BAR) system has been little investigated in the heart subjected to hypothermic ischemia. Additionally, although the hypothermic arrest is often induced in hearts with preischemic desensitization of the BAR system by preceding congestive heart failure, the functional state of the BAR system after ischemia has not been studied in these hearts. We investigated alterations in the BAR system after hypothermic ischemia in normal rat hearts and in those with preischemic desensitization of the BAR system produced with isoproterenol (ISP: 400 micrograms/kg/hr for 24 hr). Both normal and BAR-desensitized hearts were isolated and subjected either to 40 min of hypothermic (10 degrees C) global ischemia followed by 40 min of reperfusion or subjected to time-matched aerobic perfusion with modified Krebs-Henseleit solution. At the end of perfusion (1) BAR binding properties with [3H]CGP-12177 and adenylate cyclase activity were measured in crude membrane fraction and (2) the inotropic response to ISP (delta LV + dP/dtmax) was evaluated in an isovolumetric contracting heart preparation. Following reperfusion, normal hearts without desensitized BAR showed a higher Bmax value than those of nonischemic time-matched hearts (41.8 +/- 3.1 vs 35.4 +/- 2.4 fmole/mg protein, P less than 0.05), whereas the Kd value was in a similar range in the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Alterations in the beta-adrenergic receptor system after hypothermic ischemia in hearts with preischemic beta-receptor desensitization. 135 34

The effects of methylprednisolone (Solu-Medrol, CAS 83-43-2) on isoprenaline (isoproterenol)-induced decreases in the number of beta-receptors and adenylate cyclase activities in rat hearts. Rats were divided into 4 groups: 1. the control group, untreated; 2. the ISPOd group; 3. the ISP7d group, 10 mg/kg of isoprenaline was subsequently injected once a day for 6 successive days, and rats were cervically dislocated 15 h or 7 days after the last isoprenaline injection, respectively; 4. the ISP + MP7d group, 20 mg/kg of methylprednisolone was intraperitoneally injected once a day for 7 successive days following 6 successive days of isoprenaline injection, and rats were cervically dislocated. A significant decrease in the number of beta-receptors was observed (28.9 +/- 4.2 fmol/mg protein) after 6 successive isoprenaline injections compared with the control (41.7 +/- 3.6), and this significant decrease persisted for 7 days (32.6 +/- 5.8). Administration of methylprednisolone accelerated the recovery of beta-receptors (38.4 +/- 5.1) 7 days after the last isoprenaline injection. Adenylate cyclase activities were also decreased by successive isoprenaline treatments (isoprenaline-stimulated adenylate cyclase activity, 13.9 +/- 2.7 pmol/min/mg protein; basal adenylate cyclase activity, 11.2 +/- 1.7) compared with the control (isoprenaline-stimulated, 25.7 +/- 3.7; basal, 18.1 +/- 2.4). Significant decreases in adenylate cyclase activities were observed 7 days after isoprenaline administration (isoprenaline-stimulated, 17.7 +/- 3.9; basal, 14.8 +/- 2.4). Methylprednisolone also accelerated the recoveries (isoprenaline-stimulated, 20.3 +/- 2.9; basal, 17.1 +/- 3.9). These results indicate that methylprednisolone accelerated the recovery of the decrease in beta-adrenergic responsiveness caused by successive administrations of isoprenaline.
 ...
PMID:Effect of methylprednisolone on recovery of beta-adrenergic desensitization in rat hearts. 165 Feb 27