Heman airway preparations at resting tone were relaxed with either the leukotriene synthesis inhibitor BAY x1005 (3 muM), chlorpheniramine (1 muM) or the thromboxane receptor antagonist BAY u3405 (0.1 muM). The response to anti-IgE (1:1000) was 58 +/- 8% of acetylcholine pre-contraction (2.19 +/- 0.28 g). Indomethacin (3 muM) enhanced the anti-IgE-induced contraction by 28%. The anti-IgE maxima...

Cholecystokinin-octapeptide (CCK-OP) evoked contraction and 3H-acetylcholine (3H-ACh) release of the muscle strip of the guinea pig gallbladder were studied. Although hexamethonium (10(-5) M) or tetrodotoxin (10(-6) M) had no effect on CCK-OP (10(-8) M) evoked contraction and 3H-ACh release, Ca-free medium almost completely abolished CCK-OP (10(-8) M) evoked 3H-ACh release. In Ca-free medium co...

Anticholinergics are widely used for the treatment of COPD, and to a lesser extent for asthma. Primarily used as bronchodilators, they reverse the action of vagally derived acetylcholine on airway smooth muscle contraction. Recent novel studies suggest that the effects of anticholinergics likely extend far beyond inducing bronchodilation, as the novel anticholinergic drug tiotropium bromide can...

The vagus nerves of anesthetized dogs were stimulated once each cardiac cycle with a brief burst of pulses, and the timing of the stimulus bursts was changed by a fixed increment on successive cardiac cycles. The effects of such vagal stimulation on atrial contraction depended on the number of pulses per stimulus burst, on the interval between pulses within the burst, and on the timing of the s...

The involvement of muscarinic receptors in neurogenic responses of the ileum was studied in wild-type and muscarinic-receptor (M-receptor) knockout (KO) mice. Electrical field stimulation to the wild-type mouse ileum induced a biphasic response, a phasic and sustained contraction that was abolished by tetrodotoxin. The sustained contraction was prolonged for an extended period after the termina...

We evaluated the effects of aging and hypertension on endothelium-dependent relaxation of rat common carotid arteries using 14-week-old (young) and 11-month-old (old) Wistar-Kyoto rats (WKY) and age-matched spontaneously hypertensive rats (SHR). Isometric tension of common carotid artery ring segments was measured. With a resting tension of 2.0 g determined from the baseline tension-contraction...

Contractile responses of rings of ductus arteriosus from fetal and neonatal guinea pigs were studied in buffered Krebs-Henseleit solutions of various oxygen tensions. Oxygen-induced contraction of ductus arteriosus increased with gestational age, peaking at term and attenuating within 24 h after birth. Contractions of ductus in response to potassium were not different in term and preterm fetuse...

Isolated longitudinal smooth muscle from guinea pig ileum exposed to a high potassium depolarizing medium exhibited a sustained increase in muscle tone and an increase in potassium efflux. When the concentration of calcium ion in the medium was elevated the increase in muscle tone was enhanced, but the change in potassium efflux was reduced slightly. Lowering the calcium concentration diminishe...

Experiments were designed to determine the effect of Mangifera indicaLinn stembark aqueous extract on rat trachea previously incubated in presence of indomethacin, propranolol, and atropine or promethazine with histamine or acetylcholine as agonist. The strips of trachea were suspended for isometric tension recording at 37 C. M. indica aqueous extract at 2mg=ml impair the contraction induced bo...