Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0085383 (hypocapnia)
 1,697 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We studied the effect of two voltage-sensitive calcium channel blockers on Na2EDTA-induced bronchoconstriction in the canine lung periphery. A wedged bronchoscope technique was used to measure collateral system resistance before and after challenges with aerosolized Na2EDTA, hypocapnia, aerosolized acetylcholine, and increased flow of dry air in anesthetized mongrel dogs. Nifedipine, a dihydropyridine calcium channel blocker, reduced hypocapnia-induced bronchoconstriction by 88 +/- 6% (SE) but did not alter Na2EDTA-induced constriction. Verapamil, a phenylalkylamine calcium channel blocker, attenuated hypocapnia- and Na2EDTA-induced bronchoconstriction by 69 +/- 6 and 44 +/- 7%, respectively, but did not significantly alter responses to either acetylcholine or dry air challenge. We conclude that calcium influx through voltage-sensitive calcium channels, perhaps of the T subtype, has a limited role in the initiation of Na2EDTA-induced bronchoconstriction in the canine lung periphery.
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PMID:Calcium channel blockers modulate airway constriction in the canine lung periphery. 190 56

1 Because they affect isolated cerebral arteries, some calcium antagonists have been studied on the intact cerebral circulation of the rat.2 Global cerebral blood flow ((133)Xe clearance technique) was measured in anaesthetized rats. Neither perhexiline (0.1 mug/kg to 1.0 mg/kg, i.v.) nor diltiazem (0.06-0.6 mg/kg, i.v.) had any significant effect on resting cerebral blood flow when measured 5 min after each dose. A high dose of nifedipine (1.0 mg/kg, i.v.) was administered during induced hypocapnia. Nifedipine failed to modify the hypocapnic vasoconstriction of the cerebral vasculature when compared to vehicle-treated rats.3 The possibility of discrete changes in regional cerebral blood flow was investigated. Local cerebral blood flow was measured in a number of brain regions by the [(14)C]-ethanol technique 15 min after the administration of nifedipine (20 or 100 mug/kg, i.v.). Nifedipine had no apparent effect on regional blood flow in the rat brain.4 Acute arterial hypertension increases protein leakage into the brain, a phenomenon susceptible to drugs that act on endothelial pinocytosis which is known to be calcium-dependent. The increase in protein extravasation, induced by the intravenous administration of either angiotensin II or adrenaline, was unchanged in rats previously treated with either nimodipine (20 mug/kg, i.v.) or nifedipine (50 mug/kg, i.v.) when dissolved in ethanol alone. However, nifedipine (20 mug/kg, i.v.) when dissolved in a solution of polyethylene glycol and ethanol further enhanced the hypertension-induced increase in brain albumin permeability.5 In conclusion, we have been unable to demonstrate any apparent effects of various calcium antagonists on the intact cerebral circulation of the rat, despite the number of different experimental models used.
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PMID:Calcium antagonists: effects on cerebral blood flow and blood-brain barrier permeability in the rat. 687 38