Cellular and Molecular NeuroscienceResearch PaperSulforhodamine 101 induces long-term potentiation of intrinsic excitability and synaptic efficacy in hippocampal CA1 pyramidal neurons
Section snippets
Slice preparation
All experiments were carried out in compliance with the National Institute of Health Guide for the Care and Use of Laboratory Animals and in accordance with guidelines approved by the institute ethics committee for the care and use of animals. Minimal number of rats was used and animal suffering was minimized.
Brain slices were prepared as described previously (Kang et al., 1998). Briefly, 15- to 25-day-old (P15–P25) Sprague–Dawley rats (Charles River Lab., Wilmington, MA, USA) were
SR101 induces LTP-IE
To examine effects of SR101 on neuronal activity, we performed whole-cell current-clamp recording in CA1 pyramidal neurons to measure the action potential (AP) threshold with current–injection steps of 10 pA (Fig. 1A, bottom lines). The AP threshold was defined as the membrane potential at which an AP starts (Fig. 1A, dotted line). Under the control conditions, the AP threshold in pyramidal neurons is in a range of −40 to −52 mV (n=10 neurons). Perfusion of slices with SR101 (1 μM) for 10 min
Discussion
SR101 has recently been identified as a cell type-selective fluorescent marker of astrocytes, both in vivo and in slice preparations. As a result, its use as an experimental tool has rapidly accelerated, based on SR101 as a phenotypic reporter. In the present study, we have found that SR101 is also a potent bioactive compound. In particular, we observed that SR101 induced LTP-IE, increases in synaptic efficacy, and spontaneous firing in hippocampal slices. Strikingly, the concentration of SR101
Acknowledgments
This work was supported in part by grants NS38073 and NS50315 from the US National Institutes of Health and the National Institute of Neurological Disorders Stroke, grant C020925 from the NY State Spinal Cord Injury Research Board and grant 07254001 from US Army Medical Research and Material Command.
References (32)
- et al.
Developmental profile and properties of sulforhodamine 101-labeled glial cells in acute brain slices of rat hippocampus
J Neurosci Methods
(2008) - et al.
Metabotropic-mediated kainate receptor regulation of IsAHP and excitability in pyramidal cells
Neuron
(2002) Correction for liquid junction potentials in patch clamp experiments
Methods Enzymol
(1992)- et al.
Visualization of synaptic activity in hippocampal slices with FM1-43 enabled by fluorescence quenching
Neuron
(1999) Differential intracellular staining of identified neurones in Locusta with Texas Red and Lucifer Yellow
J Neurosci Methods
(1989)- et al.
A synaptic model of memory: long-term potentiation in the hippocampus
Nature
(1993) - et al.
Downregulation of dendritic I(h) in CA1 pyramidal neurons after LTP
J Neurosci
(2008) - et al.
Postfusional regulation of cleft glutamate concentration during LTP at “silent synapses.”
Nat Neurosci
(2000) - et al.
Long-term plasticity of intrinsic excitability: learning rules and mechanisms
Learn Mem
(2003) - et al.
In vivo staining of oligodendroglia in the rabbit retina
Glia
(1994)
Improved patch-clamp techniques for high-resolution current recording from cells and cell-free membrane patches
Pflugers Arch
Group I mGluRs increase excitability of hippocampal CA1 pyramidal neurons by a PLC-independent mechanism
J Neurophysiol
Astrocyte-mediated potentiation of inhibitory synaptic transmission
Nat Neurosci
Sulforhodamine labeling of neural circuits engaged in motor pattern generation in the in vitro turtle brainstem-cerebellum
J Neurosci
Sulphorhodamine-labelled cells in the neonatal rat spinal cord following chemically induced locomotor activity in vitro
J Physiol
NMDA-receptor activation increases cytoplasmic calcium concentration in cultured spinal cord neurones
Nature
Cited by (47)
Visualizing the brain's astrocytes
2019, Methods in EnzymologyCitation Excerpt :The concentration of SR101 required to efficiently label astrocytes ranges from 1 μM to upward of 250 μM. It has been shown that, upon bathing at the lower concentration of 1 μM SR101, neurons can undergo long-term potentiation of intrinsic excitability that continues past the bathing time of the cells (Kang et al., 2010). Additionally, the bolus loading of SR101 at 100 and 250 μM in the mouse cortex can induce seizure-like activity in the short period of 10 min postloading (Rasmussen, Nedergaard, & Petersen, 2016).
Monitoring gap junctional communication in astrocytes from acute adult mouse brain slices using the gap-FRAP technique
2018, Journal of Neuroscience MethodsCitation Excerpt :In our experimental condition, the use of the Aldh1L1-eGFP mouse indicated that more than 93% of the SR101 loaded cells expressed eGFP and thus were identified as astrocytes. Moreover, it has also been reported that low concentration (1 μM) of SR101 induces a direct effect on pyramidal neuron membrane structures, leading to a reduction in action potential firing threshold, and a long-term increase in neuronal excitability and synaptic efficacy (Kang et al., 2010; Garaschuk, 2013). So, we do not exclude that in our experiments such SR101-induced effects on neuronal activity occurred.
Unspecific labelling of oligodendrocytes by sulforhodamine 101 depends on astrocytic uptake via the thyroid hormone transporter OATP1C1 (SLCO1C1)
2016, Neuroscience LettersCitation Excerpt :Furthermore, this concept (Fig. 3) is supported by: (1), data suggesting that OATP1C1 is not expressed in oligodendrocytes [1]; (2), SR101 labelling of oligodendrocyte is absent in Gjc2 knock out mice that lack connexin Cx47, which is responsible for astrocyte-oligodendrocyte coupling [31]. Apart from possible false positive detection of astrocytes, SR101 application bears the risk of undesirable effects that include increased neuronal excitability and epileptic activity [6,10,23]. Since a thyroid hormone transporter is the SR101 transporter, the mechanism of the excitatory side effects needs to be discussed.
Neuroglia: Function and Pathology
2023, Neuroglia: Function and PathologyPhotonics tools begin to clarify astrocyte calcium transients
2022, NeurophotonicsUsing Genetically Encoded Calcium Indicators to Study Astrocyte Physiology: A Field Guide
2021, Frontiers in Cellular Neuroscience