Characterisation of a 5-HT7 binding site in mouse ileum

Hemedah, Maggie; Coupar, Ian M.; Mitchelson, F.

doi:10.1016/s0014-2999(99)00797-9

Cited by 8 publications

(2 citation statements)

References 33 publications

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“…In addition, the use of an antagonist as radioligand allows for circumventing the complications that arise from the presence of multiple affinity states of the receptor in native tissues (Kenakin, 1997). Interestingly, recent studies using this binding strategy have proved to be successful for labeling 5‐HT 7 ‐binding sites in the rat brain, guinea‐pig, and mouse ileum homogenates ( Hemedah et al , 1999 ; 2000).…”

Section: Introductionmentioning

confidence: 99%

Autoradiographic distribution of 5‐HT₇ receptors in the human brain using [³H]mesulergine: comparison to other mammalian species

Martín-Cora

Pazos

2004

British J Pharmacology

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1 The main aim of this investigation was to delineate the distribution of the 5-HT 7 receptor in human brain. Autoradiographic studies in guinea-pig and rat brain were also carried out in order to revisit and compare the anatomical distribution of 5-HT 7 receptors in different mammalian species. 2 Binding studies were performed in rat frontal cortex membranes using 10 nM [ 3 H]mesulergine in the presence of raclopride (10 mM) and DOI (0.8 mM). Under these conditions, a binding site with pharmacological characteristics consistent with those of the 5-HT 7 receptors was identified (rank order of binding affinity values: 5-CT45-HT45-MeOT4mesulergine Emethiothepin48-OH-3 The autoradiographic studies revealed that the anatomical distribution of 5-HT 7 receptors throughout the human brain was heterogenous. High densities were found over the caudate and putamen nuclei, the pyramidal layer of the CA2 field of the hippocampus, the centromedial thalamic nucleus, and the dorsal raphe nucleus. The inner layer of the frontal cortex, the dentate gyrus of the hippocampus, the subthalamic nucleus and superior colliculus, among others, presented intermediate concentrations of 5-HT 7 receptors. A similar brain anatomical distribution of 5-HT 7 receptors was observed in all three mammalian species studied. 4 By using [ 3 H]mesulergine, we have mapped for the first time the anatomical distribution of 5-HT 7 receptors in the human brain, overcoming the limitations previously found in radiometric studies with other radioligands, and also revisiting the distribution in guinea-pig and rat brain.

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Section: Introductionmentioning

confidence: 99%

Autoradiographic distribution of 5‐HT₇ receptors in the human brain using [³H]mesulergine: comparison to other mammalian species

Martín-Cora

Pazos

2004

British J Pharmacology

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“…Binding data was analysed using GraphPad Prism 2.0, as described by Hemedah et al (2000). Binding data was analysed using GraphPad Prism 2.0, as described by Hemedah et al (2000).…”

Section: Discussionmentioning

confidence: 99%

Nod factors activate both heterotrimeric and monomeric G-proteins in Vigna unguiculata (L.) Walp

Kelly

Irving

2003

Planta

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Nod factors are lipo-chito-oligosaccharides secreted by rhizobia that initiate many responses in the root hairs of the legume hosts, culminating in deformed hairs. The heterotrimeric G-protein agonists mastoparan, Mas7, melittin, compound 48/80 and cholera toxin provoke root hair deformation, whereas the heterotrimeric G-protein antagonist pertussis toxin inhibits mastoparan and Nod factor NodNGR[S]-(from Rhizobium sp. NGR234) induced root hair deformation. Another heterotrimeric G-protein antagonist, isotetrandrine, only inhibited root hair deformation provoked by mastoparan and melittin. These results support the notion that G-proteins are implicated in Nod factor signalling. To study the role of G-proteins at a biochemical level, we examined the GTP-binding profiles of root microsomal membrane fractions isolated from the nodulation competent zone of Vigna unguiculata (L.) Walp. GTP competitively bound to the microsomal membrane fractions labelled with [ 35 S]GTPcS, yielding a two-site displacement curve with displacement constants (K i ) of 0.58 lM and 0.16 mM. Competition with either ATP or GDP revealed a one-site displacement curve with K i of 4.4 and 29 lM, respectively, whereas ADP and UTP were ineffective competitors. The GTP-binding profiles of microsomal membrane fractions isolated from roots pretreated with either NodNGR[S] or the four-sugar, N-N'-N''-N'''-tetracetylchitotetraose (TACT) backbone of Nod factors were significantly altered compared with control microsomal fractions. To identify candidate proteins, membrane proteins were separated by SDS-PAGE and electrotransferred to nitrocellulose. GTP overlay experiments revealed that membrane fractions isolated from roots pretreated with NodNGR[S] or TACT contained two proteins (28 kDa and 25 kDa) with a higher affinity for GTPcS than control membrane fractions. Western analysis demonstrated that membranes from the pretreated roots contained more of another protein ($55 kDa) recognised by Ga common antisera. These results provide pharmacological and biochemical evidence supporting the contention that G-proteins are involved in Nod factor signalling and, importantly, implicate monomeric G-proteins in this process.

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Lysergic Acid Diethylamide (LSD) for the Treatment of Anxiety Disorders: Preclinical and Clinical Evidence

Inserra,

Piot,

De Gregorio

et al. 2023

CNS Drugs

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Characterisation of a 5-HT7 binding site in mouse ileum

Cited by 8 publications

References 33 publications

Autoradiographic distribution of 5‐HT₇ receptors in the human brain using [³H]mesulergine: comparison to other mammalian species

Autoradiographic distribution of 5‐HT₇ receptors in the human brain using [³H]mesulergine: comparison to other mammalian species

Nod factors activate both heterotrimeric and monomeric G-proteins in Vigna unguiculata (L.) Walp

Lysergic Acid Diethylamide (LSD) for the Treatment of Anxiety Disorders: Preclinical and Clinical Evidence

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Characterisation of a 5-HT7 binding site in mouse ileum

Cited by 8 publications

References 33 publications

Autoradiographic distribution of 5‐HT7 receptors in the human brain using [3H]mesulergine: comparison to other mammalian species

Autoradiographic distribution of 5‐HT7 receptors in the human brain using [3H]mesulergine: comparison to other mammalian species

Nod factors activate both heterotrimeric and monomeric G-proteins in Vigna unguiculata (L.) Walp

Lysergic Acid Diethylamide (LSD) for the Treatment of Anxiety Disorders: Preclinical and Clinical Evidence

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Product

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Autoradiographic distribution of 5‐HT₇ receptors in the human brain using [³H]mesulergine: comparison to other mammalian species

Autoradiographic distribution of 5‐HT₇ receptors in the human brain using [³H]mesulergine: comparison to other mammalian species