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Michael Stanley

Publications and source records attributed to Michael Stanley.

3 recordsLinked to original sources
PubMed2003

One- and two-photon fluorescence resonance energy transfer microscopy to establish a clustered distribution of receptor-ligand complexes in endocytic membranes.

One- and two-photon fluorescence resonance energy transfer (FRET) microscopy, using different bandwidth emission filters and a novel spectral spillover correction algorithm (PFRET algorithm), provides the basis for a quantitative approach to measure receptor clustering in endocytic membranes. Emission filters with wider bandwidth allow for an increased FRET signal and corresponding spillover. Treatment with the PFRET correction algorithm results in increasing correction levels and comparable energy transfer efficiency (E%) values, thus validating our algorithm-based approach. The relationship between E% and acceptor and donor levels and donor:acceptor (D:A) ratio is used to characterize the distribution of receptor-ligand complexes in endocytic membranes. In addition to the standard test for clustering (E%'s independence from acceptor levels), we describe a second parameter: the negative dependence of E% on increasing donor levels and D:A ratio. A donor geometric exclusion hypothesis is proposed to explain this phenomenon. One- and two-photon FRET microscopy assays show that polymeric IgA-receptor-ligand complexes are organized in clusters within apical endocytic membranes of polarized Madin-Darby canine kidney cells.

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PubMed1985

Electroconvulsive Shock and Brain Cholinergic Function: Role of Striatal Muscarinic Receptors.

Repeated administration of electroconvulsive shock (ECS) has been reported to reduce (3)H-quinuclidinyl benzilate ((3)H-QNB) binding to muscarinic cholinergic receptors in rat brain. ECS-induced muscarinic receptor subsensitivity may play a role in the therapeutic or adverse mechanisms of electroconvulsive therapy (ECT). In the present report, cataleptic responses to the muscarinic agonist, pilocarpine, were studied as a functional measure of brain muscarinic receptor sensitivity after ECS. Both single and repeated ECS administration attenuated pilocarpine-induced catalepsy, suggesting functional subsensitivity of the muscarinic receptors mediating this response. However, parallel changes were not observed in striatal muscarinic receptor binding. While repeated ECS induced a small but significant reduction in (3)H-ONB binding, single ECS marginally increased binding. The effect of pretreatment with a cholinergic antagonist (scopolamine) and with a cholinesterase inhibitor, diisopropyl fluorophosphate (DFP), on cataleptic responses was also studied. The findings demonstrated functional cholinergic subsensitivity after DFP administration and supersensitivity after scopolamine pretreatment. A clear relationship between functional alterations in muscarinic receptor sensitivity and radioligand binding parameters was not, however, established. Possible reasons for this discrepancy are discussed.

Journal Article↗