Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Intracoronary injection of papaverine is used to determine coronary flow reserve in patients. The present study was to investigate the effect of papaverine on the performance of myocardium with reduced flow reserve. In nine anaesthetized open-chest dogs a bypass from the aorta to the left circumflex coronary artery (LCX) was established. Left ventricular end-diastolic and aortic pressure, dP/dt, stroke volume, LCX blood flow, and ECG were monitored. The performance of a segment of subendocardial wall supplied by the LCX was assessed by sonomicrometry. Peak reactive hyperaemia after 15s bypass occlusion was 1.44 +/- 0.09 times the baseline flow (41 ml/min), indicating reduced coronary flow reserve. Papaverine was injected into the bypass (0.3, 0.6, 1.2, 2.5, 5.0 mg/ml, 1 ml in 15s). The maximum LCX flow following PAPA 0.3 mg was comparable to peak reactive hyperaemia, but 10-15% higher after injection of 0.6-5.0 mg papaverine. Systolic shortening of the myocardium (control: 17.5% of end-diastolic length) became reduced in a dose-dependent fashion (5-25%) for about 1 min following papaverine injection. Stroke volume (control: 0.94 +/- 0.12 ml/kg) was reduced by about 8%, left ventricular end-diastolic pressure (control: 6.2 +/- 0.8 mmHg) increased by 15%, and dP/dtmin (control: 1850 +/- 150 mmHg/s) was curtailed by 15-25%. The ECG showed a transient T inversion and S-T depression following papaverine administration and in one experiment ventricular fibrillation occurred after the injection of 2.5 mg papaverine. The observed effects of intracoronary papaverine are consistent with the theory of transient subendocardial ischaemia arising from a redistribution of blood flow from the subendocardial to the subepicardial layers, because of greater vasodilatory capacity in the latter than in the former.
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PMID:Global and regional ventricular function following intracoronary application of papaverine. 177 71

This study was performed to elucidate mechanisms responsible for the contraction of isolated canine cerebral arteries induced by uridine 5'-triphosphate (UTP) and to ascertain whether UTP given intracisternally causes cerebral arterial constriction. The latter was proven arteriographically to be the case. In vitro, UTP (10(-4)M) and UDP were similar in potency, produced sustained contractions, and were more effective than other pyrimidine nucleotides or uridine. Unlike serotonin (5-HT), UTP was not antagonized by cinanserin and failed to cause constriction of mesenteric arteries. Adenosine similarly antagonized 5-HT and UTP. The Ca2+ antagonist nimodipine abolished contractions caused by high K+ but only incompletely antagonized 5-HT or UTP. On the other hand, procedures that hyperpolarize the cell membrane (low K+ followed by K+) abolished tonic contractions induced by UTP. Hyperpolarization prior to UTP (with or without nimodipine) did not, however, prevent the occurrence of a phasic contraction. Papaverine or lanthanum antagonized this phasic response. It was concluded that UTP selectively affects cerebral arteries, may initiate contraction by releasing membrane bound Ca2+, depolarizes the cell membrane to open receptor operated and potential sensitive calcium channels, but does not inhibit the electrogenic Na-pump nor specifically antagonize the vasodilator adenosine.
Stroke
PMID:Mechanisms of the contractile effect induced by uridine 5-triphosphate in canine cerebral arteries. 665 2

Cerebral vasospasm is an important cause of delayed stroke after subarachnoid hemorrhage. Single-photon emission computed tomography (SPECT) of regional cerebral blood flow with (99m)Tc-hexamethyl propylenenamine oxime (HMPAO) was performed before and after intra-arterial papaverine treatment in 10 patients with symptomatic cerebral vasospasm. Two patients were treated twice. The ultimate clinical outcome was improved due to papaverine in 5 of the 10 patients. SPECT imaging correlated with clinical course in 10 of 12 treatments. One of the discordant cases had significant residual mesial frontal lobe perfusion defects on SPECT despite improvement in blood flow in the lateral aspects of the frontal lobes and did not improve clinically. The other was stable but required definitive treatment with balloon angioplasty on the following day before clinical improvement was noted. Papaverine has effectiveness in pharmacologically dilating constricted cerebral arteries and is preferred for distal vasospasm and in vessels that may be difficult to dilate via balloon angioplasty. Technetium-99m-HMPAO SPECT imaging detects cerebral perfusion deficits associated with vasospasm and monitors the effect of intra-arterial papaverine on regional cerebral blood flow.
J Stroke Cerebrovasc Dis 1995
PMID:Effect of intra-arterial papaverine on cerebral blood flow in vasospasm after subarachnoid hemorrhage: A study using single-photon emission computed tomography. 2648 54