Receptor

About: Receptor is a research topic. Over the lifetime, 159318 publications have been published within this topic receiving 8299881 citations.

Identification and distribution of 5-HT3 receptors in rat brain using radioligand binding.

Abstract: Functional serotonin (5-hydroxytryptamine, 5-HT) receptors have been divided into three subtypes: 5-HT1,-like, 5-HT2 and 5-HT3, (ref. 1). Brain binding sites have been identified for both the 5-HT1, and 5-HT2 subtypes. Receptors of the 5-HT3 type have been characterized on isolated peripheral tissue models such as the rat vagus nerve2, guinea-pig ileum3 and isolated rabbit heart4. Using these models, selective 5-HT3 receptor antagonists such as MDL 72222 (ref. 5), ICS 205-930 (ref. 6), GR38032F (ref. 7) and BRL 43694 (ref. 8) have been developed. Recently, GR38032F, MDL 72222 and ICS 205-930 have been shown to have behavioural effects in rodents and primates that undoubtedly reflect an action in the central nervous system (refs 9–11 and unpublished observations), suggesting the existence of 5-HT3 receptors in the brain. Here we report direct evidence for the existence of 5-HT3 receptors in rat brain tissue and their distribution, based on high affinity binding of the potent 5-HT3 receptor antagonist 3H-GR65630 to homogenates of rat entorhinal cortex. Selective 5-HT3 receptor antagonists and agonists inhibited binding of 3H-GR65630 with high affinities which correlated well with their actions on the rat isolated vagus nerve2. Binding was differentially distributed throughout the brain with high concentrations in cortical and limbic areas.

Role of IRS-2 in insulin and cytokine signalling

Abstract: THE protein IRS-1 acts as an interface between signalling proteins with Src-homology-2 domains (SH2 proteins) and the receptors for insulin, IGF-1, growth hormone, several interleukins (IL-4, IL-9, IL-13) and other cytokines1–7. It regulates gene expression and stimulates mitogenesis, and appears to mediate insulin/1GF-1-stimulated glucose transport8. Thus, survival of the IRS-1 −7− mouse with only mild resistance to insulin was surprising9'10. This dilemma is provisionally resolved with our discovery of a second IRS-signalling protein. We purified and cloned a likely candidate called 4PS from myeloid progenitor cells and, because of its resemblance to IRS-1, we designate it IRS-2. Alignment of the sequences of IRS-2 and IRS-1 revealed a highly conserved amino terminus containing a pleckstrin-homology domain and a phos-photyrosine-binding domain, and a poorly conserved carboxy terminus containing several tyrosine phosphorylation motifs. IRS-2 is expressed in many cells, including tissues from IRS-1 −/− mice11, and may be essential for signalling by several receptor systems.

Receptors for hla class-i molecules in human natural killer cells

Abstract: ▪ Abstract Natural killer cells are likely to play an important role in the host defenses because they kill virally infected or tumor cells but spare normal self-cells. The molecular mechanism that explains why NK cells do not kill indiscriminately has recently been elucidated. It is due to several specialized receptors that recognize major histocompatibility complex (MHC) class I molecules expressed on normal cells. The lack of expression of one or more class I alleles leads to NK-mediated target cell lysis. During NK cell development, the class I–specific receptors have adapted to self–class I molecules on which they recognize epitopes shared by groups of class I alleles. As such, they may fail to recognize either self-molecules that bound unusual peptides or allogeneic class I molecules unrelated to self-alleles. Different types of receptors specific for groups of HLA-C or HLA-B alleles have been identified. While in most instances, they function as inhibiting receptors, an activating form of the HLA-C...