What question did this study set out to answer?

Determine whether enteric high-affinity binding sites for serotonin represent functional neural receptors and evaluate whether dipeptides of 5-hydroxytryptophan selectively antagonize serotonin-mediated slow synaptic excitation.

July 1, 1985Journal of NeuroscienceOpen Access

Specific antagonism of enteric neural serotonin receptors by dipeptides of 5-hydroxytryptophan: evidence that serotonin is a mediator of slow synaptic excitation in the myenteric plexus

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Authors

MTMiyako TakakiNara Medical University TBTA BranchekColumbia University HTH. TamirUniversity of Bonn

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Implication

Pharmacological study reveals dipeptides of 5-hydroxytryptophan block enteric serotonin receptors in myenteric neurons, indicating serotonin mediates slow synaptic excitation.

Key Points

Determine whether enteric high-affinity binding sites for serotonin represent functional neural receptors and evaluate whether dipeptides of 5-hydroxytryptophan selectively antagonize serotonin-mediated slow synaptic excitation.
Assayed competitive binding inhibition of tritiated serotonin (3H-5-HT) in enteric membrane preparations using 5-methoxytryptamine and two dipeptides of 5-hydroxytryptophan (5-HTP-DP and N-hex-5-HTP-DP).
Recorded intracellular electrical responses of guinea pig myenteric neurons during microejection or superfusion of 5-HT, substance P, acetylcholine, and electrical stimulation of interganglionic connectives.
Both 5-HTP-DP and N-hex-5-HTP-DP competitively inhibited 3H-5-HT binding with Ki values of 0.25 µM and 1.19 µM, respectively, whereas 5-methoxytryptamine showed no binding inhibition.
Application of 10 µM 5-HTP-DP selectively blocked 5-HT-induced slow postsynaptic depolarizations and presynaptic inhibition of fast nicotinic potentials without altering responses to substance P, muscarinic acetylcholine, or action potentials.
Both dipeptides completely abolished slow excitatory postsynaptic potentials evoked by electrical stimulation of interganglionic fiber tracts in type II/AH myenteric neurons.

Cite This Study

Takaki et al. (1985) studied this question.

synapsesocial.com/papers/6a7264568031ec7bb1dd58c6 https://doi.org/10.1523/jneurosci.05-07-01769.1985

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Implication

Pharmacological study reveals dipeptides of 5-hydroxytryptophan block enteric serotonin receptors in myenteric neurons, indicating serotonin mediates slow synaptic excitation.

Specific antagonism of enteric neural serotonin receptors by dipeptides of 5-hydroxytryptophan: evidence that serotonin is a mediator of slow synaptic excitation in the myenteric plexus

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Implication

Key Points

Cite This Study

Specific antagonism of enteric neural serotonin receptors by dipeptides of 5-hydroxytryptophan: evidence that serotonin is a mediator of slow synaptic excitation in the myenteric plexus

Discussion

Member takes

Implication

Key Points

Cite This Study

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