1. The physiology of the internal anal sphincter of the vervet monkey was investigated. 2. Strips of sphincter in vitro contracted to noradrenaline and adrenaline; adrenoceptors were mainly alpha-excitatory. Strips of rectal circular muscle relaxed to noradrenaline and contained both inhibitory alpha- and beta-adrenoceptors. 3. All strips contracted to acetylcholine. After hyoscine or atropine,...

To elucidate the mechanism of cyclic nucleotides, such as adenosine 3',5'-cyclic monophosphate (cAMP) and guanosine 3',5' -cyclic monophosphate (cGMP), in the regulation of human gastric motility, we examined the effects of forskolin (FSK), isoproterenol (ISO) and sodium nitroprusside (SNP) on the spontaneous, high K(+) and acetylcholine (ACh)-induced contractions of corporal circular smooth mu...

Our previous studies have shown that the anti-asthma traditional Chinese medicine herbal formula ASHMI (anti-asthma simplified herbal medicine intervention) inhibits acetylcholine-induced contractions of tracheal rings from ovalbumin-sensitized and naive mice in a β-adrenoceptor-independent manner. We sought to determine whether acute in vivo ASHMI administration inhibits airway hyperreactivity...

The spasmolytic properties of the aqueous extract of Aframomum melegueta (K Schum) and Citrus aurantifolia (Christm and Panzer) (AMCA) mixture were tested on isolated rat trachea. Inhibition of the contraction was observed the in presence of the AMCA (EC 50 = 1.80 ± 0.48 mg/mL) after a pre contraction of the trachea by acetylcholine (10⁻⁵ M). With propranolol (10⁻⁶ M), the spasmolytic activity ...

EDITORIAL SYNOPSiS A study of the response of the ileocaeco-colic sphincter2 of the cat and dog to sympathomimetic and parasympathomimetic drugs and to stimulation of the autonomic nerves is reported. The response to drugs in vivo is identical with that previously noted in vitro, namely, contraction of the sphincter by adrenaline, noradrenaline, and acetylcholine, and relaxation by isoprenaline...

Purinoceptor-mediated responses were characterized in the ileum of Suncus murinus. Adenosine as well as adenosine 5'-triphosphate (ATP) contracted the ileum in a concentration-dependent manner. Contractile responses to transmural electrical stimulation were attenuated by adenosine only at high concentrations. Theophylline competitively blocked the adenosine-induced contraction. Atropine also in...

The purpose of this study was the effect of epithelium damage on mechanical responses of airway smooth muscles under different resting tension. We performed acetylcholine (ACh) (10(-5) M)-induced contraction on tracheal strips from 30 rabbits in five groups (0.5, 1, 1.5, 2 and 2.5 g) before and after epithelium removal. At low resting tension (0.5-1.5 g), the epithelium removal decreased the AC...