Therapeutic efficacy of α7 ligands after acute ischaemic stroke is linked to conductive states of α7 nicotinic ACh receptors
| Autor: | Graham Beaton, Fabio C. Tucci, William R. Kem, Nikhil Gaidhani, Victor V. Uteshev |
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| Rok vydání: | 2020 |
| Předmět: |
0301 basic medicine
Agonist alpha7 Nicotinic Acetylcholine Receptor medicine.drug_class Pharmacology Receptors Nicotinic Ligands Neuroprotection Partial agonist Brain Ischemia 03 medical and health sciences 0302 clinical medicine medicine Animals Stroke Acetylcholine receptor Ischemic Stroke business.industry medicine.disease 030104 developmental biology Nicotinic agonist Metabotropic receptor business 030217 neurology & neurosurgery Ionotropic effect |
| Zdroj: | British journal of pharmacologyREFERENCES. 178(7) |
| ISSN: | 1476-5381 |
| Popis: | BACKGROUND AND PURPOSE Targeting α7 nicotinic ACh receptors (nAChRs) in neuroinflammatory disorders including acute ischaemic stroke holds significant therapeutic promise. However, therapeutically relevant signalling mechanisms remain unidentified. Activation of neuronal α7 nAChRs triggers ionotropic signalling, but there is limited evidence for it in immunoglial tissues. The α7 ligands which are effective in reducing acute ischaemic stroke damage promote α7 ionotropic activity, suggesting a link between their therapeutic effects for treating acute ischaemic stroke and activation of α7 conductive states. EXPERIMENTAL APPROACH This hypothesis was tested using a transient middle cerebral artery occlusion (MCAO) model of acute ischaemic stroke, NS6740, a known selective non-ionotropic agonist of α7 nAChRs and 4OH-GTS-21, a partial α7 agonist. NS6740-like ligands exhibiting low efficacy/potency for ionotropic activity will be referred to as non-ionotropic agonists or "metagonists". KEY RESULTS 4OH-GTS-21, used as a positive control, significantly reduced neurological deficits and brain injury after MCAO as compared to vehicle and NS6740. By contrast, NS6740 was ineffective in identical assays and reversed the effects of 4OH-GTS-21 when these compounds were co-applied. Electrophysiological recordings from acute hippocampal slices obtained from NS6740-injected animals demonstrated its remarkable brain availability and protracted effects on α7 nAChRs as evidenced by sustained (>8 h) alterations in α7 ionotropic responsiveness. CONCLUSION AND IMPLICATIONS These results suggest that α7 ionotropic activity may be obligatory for therapeutic efficacy of α7 ligands after acute ischaemic stroke yet, highlight the potential for selective application of α7 ligands to disease states based on their mode of receptor activation. |
| Databáze: | OpenAIRE |
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