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1. The aim of this study was the pharmacological characterization of tachykinin NK1 and NK2 receptors mediating contraction in the circular muscle of the guinea-pig ileum and proximal colon. The action of substance P (SP), neurokinin A (NKA) and of the synthetic agonists [Sar9]SP sulphone, [Glp6,Pro9]SP(6-11) (septide) and [beta Ala8]NKA(4-10) was(More)
1. We have studied the mechanical response of circular strips of the guinea-pig ileum to tachykinins and characterized the receptors involved by means of receptor-selective agonists. 2. The strips responded to both substance P (SP) and neurokinin A (NKA), as well as to [Pro9]-SP sulphone (selective NK1-receptor agonist), [beta Ala8]-NKA(4-10) (selective(More)
The interaction of Otilonium bromide (OB) with binding sites for 63 different receptors and ion channels in appropriate preparations has been investigated. Experiments were also performed in rat colon, the preferred tissue for OB 'in vivo' uptake after oral administration. Among the receptors investigated OB binds with sub microM affinity to muscarinic M1,(More)
AF-DX 116 (see chemical name below) is a competitive antagonist of muscarine receptors in peripheral organs. In contrast to pirenzepine, its behaviour in functional experiments indicates selectivity for the M2 muscarinic subtype. In pithed rats AF-DX 116 inhibits vagally-induced bradycardia, an M2 response, (ED50 32 micrograms/kg i.v.) in preference to the(More)
The M2 subtype of the muscarinic receptor was investigated using the antagonist AF-DX 116. In "in vitro" and "in vivo" experiments, AF-DX 116 behaved as a competitive antagonist and exhibited a selectivity for cardiac muscarinic-mediated functions. It antagonized negative chronotropic and inotropic effects exerted by muscarinic receptor activation in the(More)
Prejunctional affinity constants of the cardioselective muscarine receptor antagonist AF-DX 116 (11-[(2[(diethyl-amino)methyl]-1-piperidinyl)acetyl]-5,11-dihydro6 H-pyrido [2,3-b] [1,4] benzodiazepine-6-one) were determined for muscarine autoreceptors on cholinergic nerves of the guinea-pig ileum and for heteroreceptors on noradrenergic nerves of the rat(More)
We examined the effect of the muscarinic agonist McN-A-343 (4-m-chlorophenylcarbamoyloxy-2-butynyl trimethyl ammonium) on in vitro preparations of rat small intestine. McN-A-343 (0.1-10 microM) induced a concentration-dependent relaxation of duodenum, jejunum and ileum. This effect was due to activation of muscarinic receptors of the M1 subtype, inasmuch as(More)
The present study deals with the EEG (electroencephalogram) and behavioural effects of a subconvulsant dose (30 mg/kg i.p.) of pentylenetetrazole in freely moving rats pretreated (100 mg/kg p.o., 1 h before pentylenetetrazole) with two classic (theophylline and caffeine) and two new (enprofylline and isbufylline) xanthines. In rats treated with vehicle,(More)