{"doi":"10.1042/bj2580023","title":"Accumulation of inositol polyphosphate isomers in agonist-stimulated cerebral-cortex slices. Comparison with metabolic profiles in cell-free preparations","abstract":"<jats:p>1. Basal and carbachol-stimulated accumulations of isomeric [3H]inositol mono-, bis-, tris- and tetrakis-phosphates were examined in rat cerebral-cortex slices labelled with myo-[2-3H]inositol. 2. In control samples the major [3H]inositol phosphates detected were co-eluted on h.p.l.c. with Ins(1)P, Ins(4)P (inositol 1- and 4-monophosphate respectively), Ins(1,4)P2 (inositol 1,4-bisphosphate), Ins(1,4,5)P3 (inositol 1,4,5-tris-phosphate) and Ins(1,3,4,5)P4 (inositol 1,3,4,5-tetrakisphosphate). 3. After stimulation to steady state with carbachol, accumulation of each of these products was markedly increased. 4. Agonist stimulation, however, also evoked much more dramatic increased accumulations of a second [3H]inositol trisphosphate, which was co-eluted on h.p.l.c. with authentic Ins(1,3,4)P3 (inositol 1,3,4-trisphosphate) and of three further [3H]inositol bisphosphates ([3H]InsP2(s]. 5. Examination of the latter by chemical degradation by periodate oxidation and/or h.p.l.c. allowed identification of these as [3H]Ins(1,3)P2, [3H]Ins(3,4)P2 and [3H]Ins(4,5)P2 (inositol 1,3-, 3,4- and 4,5-bisphosphates respectively), which respectively accounted for about 22%, 8% and 3% of total [3H]InsP2 in extracts from stimulated tissue slices. 6. By using a h.p.l.c. method which clearly resolves Ins(1,3,4,5)P4 and Ins(1,3,4,6)P4 (inositol 1,3,4,6-tetrakisphosphate), only the former isomer could be detected in extracts from either control or stimulated tissue slices. Similarly, [3H]inositol pentakis- and hexakis-phosphates were not detectable either in the presence or absence of carbachol under the radiolabelling conditions described. 7. The catabolism of [3H]Ins(1,4,5)P3 and [3H]Ins(1,3,4)P3 by cell-free preparations from cerebral cortex was also studied. 8. In the presence of Mg2+, [3H]Ins(1,4,5)P3 was specifically dephosphorylated via [3H]Ins(1,4)P2 and [3H]Ins(4)P to free [3H]inositol, whereas [3H]Ins(1,3,4)P3 was degraded via [3H]Ins(3,4)P2 and, to a lesser extent, via [3H]Ins(1,3)P2 to D- and/or L-[3H]Ins(1)P and [3H]inositol. 9. In the presence of EDTA, hydrolysis of [3H]Ins(1,4,5)P3 was greater than or equal to 95% inhibited, whereas [3H]Ins(1,3,4)P3 was still degraded, but yielded only a single [3H]InsP2 identified as [3H]Ins(1,3)P2. 10. The significance of these observations with cell-free preparations is discussed in relation to the proportions of the separate isomeric [3H]inositol phosphates measured in stimulated tissue slices.</jats:p>","journal":"Biochemical Journal","year":1989,"id":38548,"datarank":3.1331045405812374,"base_score":4.248495242049359,"endowment":4.248495242049359,"self_citation_contribution":0.637274286307404,"citation_network_contribution":2.4958302542738333,"self_endowment_contribution":0.637274286307404,"citer_contribution":2.4958302542738333,"corpus_percentile":null,"corpus_rank":null,"citation_count":69,"citer_count":50,"citers_with_citation_signal":44,"citers_with_endowment":44,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":null,"is_data_producer":false,"deposit_databanks":null,"is_oa":false,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":null,"fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":184930,"name":"A J Letcher","orcid":null,"position":1,"is_corresponding":false},{"id":191079,"name":"S R Nahorski","orcid":null,"position":2,"is_corresponding":false},{"id":191078,"name":"I H Batty","orcid":null,"position":0,"is_corresponding":false}],"reference_count":0,"raw_metadata":{"has_enrichment":true,"base_score":4.248495242049359,"endowment":4.248495242049359,"datacite_reuse_total":0,"file_count":0,"downloads":0,"views":0,"has_version_chain":false,"is_dataset":false,"is_oa":false,"pmid":"2930510","pmcid":"PMC1138319","openalex_id":"https://openalex.org/W2173293374","authors":[],"funders":[{"funder_name":"Wellcome Trust","grant_id":"","title":null},{"funder_name":"Wellcome Trust","grant_id":"","title":null}],"total_grants":2,"fwci":15.331,"citation_percentile":0.99494466,"influential_citations":0,"citation_trend":[],"oa_status":"bronze","license":null,"oa_locations":[{"url":"https://portlandpress.com/biochemj/article-pdf/258/1/23/596251/bj2580023.pdf","host_type":"journal"},{"url":"https://europepmc.org/articles/pmc1138319?pdf=render","host_type":"GREEN"},{"url":"https://portlandpress.com/biochemj/article-pdf/258/1/23/596251/bj2580023.pdf","host_type":"publisher"},{"url":"https://doi.org/10.1042/bj2580023","host_type":"journal"},{"url":"https://pubmed.ncbi.nlm.nih.gov/2930510","host_type":"repository"},{"url":"https://www.ncbi.nlm.nih.gov/pmc/articles/1138319","host_type":"repository"}],"fields_of_study":["Trace Elements in Health","Phytase and its Applications","Protein Kinase Regulation and GTPase Signaling","Chemistry","Medicine","Biology","Animals","Carbachol","Cell-Free System","Cerebral Cortex","Chromatography, High Pressure Liquid","Hydrolysis","In Vitro Techniques","Inositol Phosphates","Isomerism","Male","Rats","Rats, Inbred Strains","Sugar Phosphates"],"mesh_terms":["Animals","Carbachol","Cell-Free System","Cerebral Cortex","Chromatography, High Pressure Liquid","Hydrolysis","Inositol Phosphates","Isomerism","Male","Rats, Inbred Strains","Sugar Phosphates","Rats","In Vitro Techniques"],"keywords":["Inositol","Inositol phosphate","Sugar phosphates","Carbachol","Chemistry","Tris","Stimulation","Phosphocreatine","Cyclitol","Biochemistry","Phosphate","Endocrinology","Biology","Receptor"],"sdg_mappings":[{"sdg_number":0,"sdg_label":"Clean water and sanitation"}],"linked_datasets":[],"clinical_trials":[],"software_tools":[],"database_accessions":[],"source":"live","citation_network_status":"fetched"},"created_at":"2026-06-11T04:13:38.224667Z","pmid":null,"pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}