Study of the contractile effect of 5-hydroxytryptamine (5-HT) in the isolated longitudinal muscle strip from guinea-pig ileum

  title={Study of the contractile effect of 5-hydroxytryptamine (5-HT) in the isolated longitudinal muscle strip from guinea-pig ileum},
  author={Karl Heinz Buchheit and G{\"u}nter Engel and Ernst Mutschler and Brian P. Richardson},
  journal={Naunyn-Schmiedeberg's Archives of Pharmacology},
Summary1.The contractile effect of 5-HT in the isolated longitudinal ileal muscle of adult guinea-pigs was studied over a large concentration range.2.5-HT produced a biphasic concentration-response curve indicative of an interaction with at least two indenpendent populations of receptors. The concentrations which elicited half-maximal effects for the first and the second phases of the concentration-response curve were estimated as 1.5±1.2×10−8 mol/l and 1.3±0.4×10−6 mol/l respectively. The… 

Characterization of 5-HT receptors mediating contraction and relaxation of the longitudinal muscle of guinea-pig distal colon in vitro

Five receptors through which 5-hydroxytryptamine contracts and relaxes the longitudinal muscle of segments of guinea-pig distal colon, in vitro are characterized and it is concluded that 5-HT3, 5- HT4 and5-HT1-like receptors mediate contraction of the longitudinal Muscle of the distal Colon.

Effects of 5-HT4 receptor stimulation on basal and electrically evoked release of acetylcholine from guinea-pig myenteric plexus

5-methoxytryptamine may both inhibit (via 5-HT1 receptors) and facilitate (via5-HT4 receptors) the evoked release of acetylcholine from guinea-pig myenteric neurones and the facilitatory action is unmasked when the 5- HT1 receptor is blocked by methiothepine.

Cisplatin increases the release of 5-hydroxytryptamine (5-HT) from the isolated vascularly perfused small intestine of the guinea-pig: Involvement of 5-HT3 receptors

Cisplatin, at concentrations which occur during anti-cancer therapy in humans and induce emesis, increases the release of 5-HT from the enterochromaffin cells of the small intestine of the guinea-pig.

Modulation by 5-HT3 and 5-HT4 receptors of the release of 5-hydroxytryptamine from the guinea-pig small intestine

The results suggest that enterochromaffin cells of the guinea-pig ileum do not contain 5-HT1 and5-HT2 receptors, but are endowed with 5- HT3 and 5-ht4 autoreceptors, which triggers a positive feedback mechanism leading to an increase of 5-hydroxytryptamine release.

5-HT1D and 5-HT4 Receptor Agonists Stimulate the Peristaltic Reflex in the Isolated Guinea Pig Ileum

5-HT stimulates the peristaltic reflex in the isolated guinea pig ileum by activation of 5-HT4 and 5- HT1D receptors; other 5-ht receptor subtypes appear not to play a significant role in the modulation of this reflex.

Both exogenous 5-HT and endogenous 5-HT, released by fluoxetine, enhance distension evoked propulsion in guinea-pig ileum in vitro

Results indicate that luminal application of exogenous 5-HT, or increased release of endogenous mucosal5-HT above basal levels, acts to lower the threshold for propulsive contractions in the guinea-pig ileum via activation of 5- HT3 and 4-HT4 receptors and the release of tachykinins.

Effect of 5-hydroxytryptamine and its antagonists on colonic smooth muscle of the rabbit

5HT affects colonic contraction by a direct effect on muscle and indirectly through the enteric nerves and 5HT inhibits neurons responsible for the off-contraction in distal circular muscle without affecting the on-contracted muscle.

5-Methoxytryptamine and 2-methyl-5-hydroxytryptamine-induced desensitization as a discriminative tool for the 5-HT3 and putative 5-HT4 receptors in guinea pig ileum

It is concluded that 5-methoxytryptamine and 2-methyl-5-HT can be utilized as selective probes to discriminate the putative 5-HT4 receptor from the 5- HT3 receptor in guinea pig ileum.



Substance P mediates atropine-sensitive response of guinea-pig ileum to serotonin.

  • L. Chahl
  • Biology, Chemistry
    European journal of pharmacology
  • 1983

An analysis of the direct and indirect actions of drugs on the isolated guinea-pig ileum.

  • M. DayJ. Vane
  • Biology, Chemistry
    British journal of pharmacology and chemotherapy
  • 1963
It is concluded that morphine is only a partial antagonist of 5-hydroxytryptamine receptors in nervous tissue and that phenoxybenzamine antagonizes more 5-Hydroxyt Kryptamine receptors than those in smooth muscle.

The effects of metoclopramide on acetylcholine release and on smooth muscle response in the isolated guinea-pig ileum

The effects of metoclopramide on both longitudinal muscle contraction and resting release of labelled acetylcholine were prevented in the presence of a concentration of 5-hydroxytryptamine (5-HT) that desensitized 5-HT receptors, suggesting that metoclobramide stimulates neuronal 5- HT receptors and, thereby, facilitates acetyl choline release.

Receptors for 5-hydroxytryptamine on the sympathetic nerves of the rabbit heart

Summary1.The Langendorff perfused rabbit heart has been used to investigate the effects of 5-hydroxytryptamine (5-HT) and several closely related analogues as stimulants and inhibitors of transmitter

Evidence that the contractile response of the guinea-pig ileum to capsaicin is due to substance P release

  • L. Chahl
  • Biology, Medicine
    Naunyn-Schmiedeberg's Archives of Pharmacology
  • 2004
It is proposed that capsaicin releases substance P from neurones in the ileum, and the released substance P in turn stimulates cholinergic neurones to release acetylcholine, as well as producing direct muscle contraction.

Release of substance P from the enteric nervous system: direct quantitation and characterization.

The ability of electrical stimulation to release SP from the myenteric plexus in amounts sufficient to produce a physiological response in a Ca++- and temperature-dependent fashion in combination with data provided by indirect pharmacological experiments strongly suggests that SP functions as a neurotransmitter in the enteric nervous system.

Direct evidence of acetylcholine releasing effect of serotonin in the Auerbach plexus

In the presence of atropine (2×10−8 M) a 9 times higher concentration of serotonin was needed to produce the same contraction of the ileum as in control experiments, indicating that the contractile effect of serotonin on the longitudinal muscle of ileu might be mediated via a cholinergic pathway.

(±)[125Iodo]cyanopindolol, a new ligand for β-adrenoceptors: Identification and quantitation of subclasses of β-adrenoceptors in guinea pig

The low dissociation constant of ICYP in combination with its high specific radioactivity allows binding studies to be carried out with small protein and ligand concentrations, e.g. 3 μg protein per assay in guinea pig lung membranes.

Substance P antagonists active in vitro and in vivo.