Chr Ivancheva

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1. The interaction of nitric oxide and ATP in the non-adrenergic, non-cholinergic (NANC) motor responses and the presence of NADPH-diaphorase and quinacrine-positive myenteric neurones were studied on guinea-pig ileum using mechanographic, histochemical and quinacrine-fluorescence techniques. In the presence of phentolamine, propranolol and atropine, the(More)
1 A triple organ bath method allowing the synchronous recording of the motor activity of the circular muscle layer belonging to the oral and anal segments of guinea-pig small intestine adjacent to an electrically stimulated middle segment was developed to study the ascending and descending reflex motor responses. 2 Electrical field stimulation (0.8 ms, 40(More)
Spontaneous or electrically elicited contraction and/or relaxation of the longitudinal and circular muscles of the colon and rectum and the anal canal in rat segment preparations were recorded simultaneously to display contractile potency and functional coordination of muscles in the large intestine. Spontaneous high-amplitude contractions, but not(More)
A triple organ bath was developed to study the ascending and descending reflexes in a guinea pig small intestine model, allowing synchronous recording the motor activity of the longitudinal and circular muscle layers belonging to the oral and anal part of segment preparations. Field electrical stimulation (0.8 msec, 40 V, 5 Hz, 10 sec) applied either to the(More)
Met-enkephalin-induced modulation of tetrodotoxin (0.1 microM)-sensitive nonadrenergic, noncholinergic (NANC) nerve-mediated responses of the longitudinal muscle layer of guinea pig ileum during electrical field stimulation (EFS, 0.8 ms, 40 V, 20 s, 1 Hz or 10 Hz) were studied. The response to EFS of untreated preparations was a twitch followed by a(More)
1. Effects of the enkephalins Met-enk (M) and Leu-enk (L), of two newly synthesized analogues--[Cys-(O2NH2)]2-Met-enk (CM) and [Cys-(O2NH2)]2-Leu-enk (CL)--and of a hexapeptide--D-Ala2-Leu5-Arg6 (Dalargin; DL) on the spontaneous and electrically stimulated activity were examined with respect to their selectivity for the mu opioid receptors in the(More)
The involvement of nitric oxide and ATP in both spontaneous and electrically-induced nonadrenergic noncholinergic (NANC) motor activity with special interest in the apamin-sensitive mechanisms was studied in a guinea pig ileum model. Depending on the concentration (0.1 or 1 micromol/l), apamin, a blocker of the calcium-activated potassium channels and(More)
1. The pattern of responses of longitudinally oriented guinea pig ileum organ bath preparations was studied during short- (1-5 sec) or long-lasting (20 sec) electrical field stimulation (EFS, 0.8 msec, 40 V, 1-20 Hz). 2. In the presence of phentolamine (5 microM), propranolol (5 microM), and atropine (3 microM), the EFS elicited nonadrenergic,(More)
1 The effect of short-term exposure to cupric ions (Cu2+) on electric field-stimulated (EFS) or agonist-induced contractions of guinea-pig isolated ileum was studied. 2 EFS elicited tetrodotoxin- and atropine-sensitive contractions that were concentration dependently inhibited by Cu2+ (IC50 = 14.7 +/- 4.2 microm). Maximal inhibition (90.4 +/- 3.1% of(More)
1. The possible contribution of the nonadrenergic noncholinergic (NANC) transmitters nitric oxide (NO) and substance P (SP) to the contractility of guinea pig isolated ileum was studied by the responses of the longitudinal muscle to electrical field stimulation (0.8 msec, 40 V, 1-20 Hz, 20 sec) of the intrinsic nerves and by the presence and distribution of(More)