Heterogeneity of 5‐hydroxytryptamine receptors in the rat uterus and stomach strip

Wrigglesworth, Susan

doi:10.1111/j.1476-5381.1983.tb10059.x

Cited by 18 publications

(7 citation statements)

References 20 publications

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“…Cyproheptadine showed the opposite response, reducing spiking activity in the proximal sites and not in the ileum. These results suggest a heterogeneity of 5-HT receptors as has been found between different tissues (27).…”

Section: Mechanisms Of 5-ht-induced Stimulationsupporting

confidence: 63%

Involvement of 5‐Hydroxytryptamine in Canine Intestinal Motility Patterns

Davidson

Pilot

Thompson

1990

Neurogastroenterology Motil

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Fasting activity seen as migrating myoelectric complexes and postprandial activity was recorded from eight conscious dogs with monopolar electrodes implanted on the serosa of the small bowel. A basal period was recorded, after which the 5‐hydroxytryptamine (5‐HT) antagonists methysergide, ketanserin, ICS 205–930, cyproheptadine, or MDL 72222 were administered by intravenous infusion. In other fasted experiments the same antagonists were administered in combination with a 5‐HT infusion. Ketanserin did not change the fed or fasted pattern in the intestine. Methysergide induced irregular spiking activity at all electrode sites in both preprandial and postprandial experiments which continued to the end of recording. Cyproheptadine prevented the distal propagation of phase III of the complex beyond the jejunum. Antagonists of the 5‐HT3 receptor abolished phase II of the complex in some experiments. In postprandial experiments these antagonists increased the spiking activity recorded. 5‐HT itself produced irregular spiking, which in the proximal electrodes only was reduced by concurrent ketanserin administration. These data indicate a role for endogenous 5‐HT in the production of phase II of the migrating myoelectric complex and in its distal migration. The stimulatory action of 5‐HT in the proximal intestine is mediated by 5‐HT2 receptors. Distally 5‐HT3 receptors can play an inhibitory role in the contractile response.

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Section: Mechanisms Of 5-ht-induced Stimulationsupporting

confidence: 63%

Involvement of 5‐Hydroxytryptamine in Canine Intestinal Motility Patterns

Davidson

Pilot

Thompson

1990

Neurogastroenterology Motil

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“…Both of these compounds selectively displace [3H]-spiperone from central 5-HT2 binding sites and both exhibit a high affinity for these sites (Riblet & Taylor, 1981;Leysen et al, 1981). The compounds have also been shown to potently antagonize 5-HT contractions in a variety of isolated smooth muscles (Brazenor & Angus, 1982;Humphrey et al, 1982;Cohen et al, 1983;Ichida et al, 1983;Wrigglesworth, 1983;Clancy & Maayani, 1985). In the present experiments, spiperone expressed a similar potency in the rat jugular vein, rat caudal artery and rabbit aorta although the pKB value measured in the aorta was significantly different from the pKBs obtained in either of the other two.…”

Section: Discussionmentioning

confidence: 99%

“…Various smooth muscle 5-HT receptors have been claimed to exist Feniuk et al, 1983a, b;Wrigglesworth, 1983;Humphrey, 1984;Cohen et al, 1985)., but only in the case of the so-called 5-HT2 receptor are potent and selective competitive antagonists reported to be available. Many antagonists, notably spiperone and ketanserin, have emerged from radioligand binding studies where they demonstrated high affinity for 5-HT2 binding sites in the brain (Peroutka & Snyder, 1979, 198 1;Leysen et al, 1982;Engel et al, 1984).…”

Section: Introductionmentioning

confidence: 99%

Peripheral 5‐HT₂‐like receptors. Can they be classified with the available antagonists?

Leff

Martin

1986

British J Pharmacology

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1 Interactions between 5-hydroxytryptamine (5-HT) and the so-called 5-HT2 receptor antagonists ketanserin, spiperone, trazodone and methysergide were studied in isolated preparations of the rabbit aorta, rat jugular vein, and rat caudal artery. 2 Trazodone and spiperone were apparently simple competitive antagonists since they produced antagonism that was surmountable over the concentration range studied and, in each tissue, their apparent affinity appeared to be independent of the antagonist concentration. Furthermore, concentration-ratios obtained with the two antagonists in combination suggested that antagonism was additive, implying mutual competition with a single population of 5-HT receptors. 3 Ketanserin was a non-surmountable antagonist of 5-HT in the rat caudal artery and methysergide demonstrated surmountable, competitive antagonism only in the rabbit aorta. 4 Antagonist dissociation constants estimated for apparently competitive interactions showed that ketanserin, spiperone and trazodone expressed affinities which differed according to the tissue used. In the case of trazodone, affinity estimates differed by as much as 12 fold. These discrepancies were independent of the 5-HT receptor agonist used and could not be attributed to an inadequate equilibration of the antagonist. 5These results can be interpreted in two ways: either the receptors in the different tissues are heterogeneous or the antagonists used here must be considered as unreliable probes for the classification of 5-HT2-like receptors.

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“…Current ideas indicate the presence of multiple 5-HT binding sites in rat brain, designated 5HTIA, SHTIB, SHTlc and 5HT2 (Hoyer et a1 1985;Leff & Martin 1988) and may explain the Hill coefficient of less than 1 for 5-HT displacement This is the first report of a specific [3H]5-HT binding site in rat myometrium. Although this is presumably the 5-HT2 receptor described in functional studies (Wigglesworth 1983;Bradley et a1 1986;Hollingsworth et a1 1988), further data are necessary for more conclusive support for this idea. A Hill coefficient not different from one suggests a single type of 5-HT binding site.…”

Section: Discussionmentioning

confidence: 88%

Ergometrine and 5-hydroxytryptamine binding sites in rat brain and myometrium

Hollingsworth

Dascombe

Price

et al. 1989

Journal of Pharmacy and Pharmacology

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Functional studies suggest that ergometrine is a partial agonist involving 5-hydroxytryptamine (5-HT) receptors in rat uterus. Ergometrine displaced [3H]5-HT from specific binding sites in rat brain, but did not displace [3H]5-HT at functionally important concentrations in rat myometrium. These binding studies indicate that the agonist and antagonist actions of ergometrine in rat uterus arise from its initial interaction with binding sites other than those for 5-HT.

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Heterogeneity of 5‐hydroxytryptamine receptors in the rat uterus and stomach strip

Cited by 18 publications

References 20 publications

Involvement of 5‐Hydroxytryptamine in Canine Intestinal Motility Patterns

Involvement of 5‐Hydroxytryptamine in Canine Intestinal Motility Patterns

Peripheral 5‐HT₂‐like receptors. Can they be classified with the available antagonists?

Ergometrine and 5-hydroxytryptamine binding sites in rat brain and myometrium

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Heterogeneity of 5‐hydroxytryptamine receptors in the rat uterus and stomach strip

Cited by 18 publications

References 20 publications

Involvement of 5‐Hydroxytryptamine in Canine Intestinal Motility Patterns

Involvement of 5‐Hydroxytryptamine in Canine Intestinal Motility Patterns

Peripheral 5‐HT2‐like receptors. Can they be classified with the available antagonists?

Ergometrine and 5-hydroxytryptamine binding sites in rat brain and myometrium

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Peripheral 5‐HT₂‐like receptors. Can they be classified with the available antagonists?