scholarly journals Excitation of medium spiny neurons by ‘inhibitory’ ultrapotent chemogenetics via shifts in chloride reversal potential

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Stephanie C Gantz ◽  
Maria M Ortiz ◽  
Andrew J Belilos ◽  
Khaled Moussawi
Keyword(s):  
Brain Slices ◽  
Reversal Potential ◽  
Cell Types ◽  
Receptor Activation ◽  
D1 Receptor ◽  
Medium Spiny Neurons ◽  
Inhibitory Function ◽  
Spiny Neurons

Ultrapotent chemogenetics, including the chloride-permeable inhibitory PSAM4-GlyR receptor, were recently proposed as a powerful strategy to selectively control neuronal activity in awake, behaving animals. We aimed to validate the inhibitory function of PSAM4-GlyR in dopamine D1 receptor-expressing medium spiny neurons (D1-MSNs) in the ventral striatum. Activation of PSAM4-GlyR with the uPSEM792 ligand enhanced rather than suppressed the activity of D1-MSNs in vivo as indicated by increased c-fos expression in D1-MSNs and in vitro as indicated by cell-attached recordings from D1-MSNs in mouse brain slices. Whole-cell recordings showed that activation of PSAM4-GlyR depolarized D1-MSNs, attenuated GABAergic inhibition, and shifted the reversal potential of PSAM4-GlyR current to more depolarized potentials, perpetuating the depolarizing effect of receptor activation. These data show that ‘inhibitory’ PSAM4-GlyR chemogenetics may activate certain cell types and highlight the pitfalls of utilizing chloride conductances to inhibit neurons.

scholarly journals Inhibitory ultrapotent chemogenetics activate dopamine D1 receptor-expressing medium spiny neurons

2020 ◽  
Author(s):  
Stephanie C. Gantz ◽  
Maria M. Ortiz ◽  
Andrew J. Belilos ◽  
Khaled Moussawi
Keyword(s):  
Brain Slices ◽  
Reversal Potential ◽  
Cell Types ◽  
Receptor Activation ◽  
Dopamine D1 Receptor ◽  
D1 Receptor ◽  
Medium Spiny Neurons ◽  
Inhibitory Function ◽  
Spiny Neurons

SUMMARYUltrapotent chemogenetics, including the chloride-permeable inhibitory PSAM4-GlyR receptor, were recently proposed as a powerful strategy to selectively control neuronal activity in awake, behaving animals. We aimed to validate the inhibitory function of PSAM4-GlyR in dopamine D1 receptor-expressing medium spiny neurons (D1-MSNs) in the ventral striatum. Activation of PSAM4-GlyR with the uPSEM792 ligand enhanced rather than suppressed the activity of D1-MSNs in vivo as indicated by increased c-fos expression in D1-MSNs. Whole-cell recordings in mouse brain slices showed that activation of PSAM4-GlyR did not inhibit firing of action potentials in D1-MSNs. Activation of PSAM4-GlyR depolarized D1-MSNs, attenuated GABAergic inhibition, and shifted the reversal potential of PSAM4-GlyR current to more depolarized potentials, perpetuating the depolarizing effect of receptor activation. The data show that ‘inhibitory’ PSAM4-GlyR chemogenetics may actually activate certain cell types, and highlight the pitfalls of utilizing chloride conductances to inhibit neurons.

Dopamine Modulates Excitability of Basolateral Amygdala Neurons In Vitro

2005 ◽  
Vol 93 (3) ◽  
pp. 1598-1610 ◽  
Author(s):  
Sven Kröner ◽  
J. Amiel Rosenkranz ◽  
Anthony A. Grace ◽  
German Barrionuevo
Keyword(s):  
Basolateral Amygdala ◽  
Neuronal Response ◽  
Brain Slices ◽  
Receptor Activation ◽  
D1 Receptor ◽  
In Vivo Studies ◽  
Projection Neurons ◽  
Direct Effects

The amygdala plays a role in affective behaviors, which are modulated by the dopamine (DA) innervation of the basolateral amygdala complex (BLA). Although in vivo studies indicate that activation of DA receptors alters BLA neuronal activity, it is unclear whether DA exerts direct effects on BLA neurons or whether it acts via indirect effects on BLA afferents. Using whole cell patch-clamp recordings in rat brain slices, we investigated the site and mechanisms through which DA regulates the excitability of BLA neurons. Dopamine enhanced the excitability of BLA projection neurons in response to somatic current injections via a postsynaptic effect. Dopamine D1 receptor activation increased excitability and evoked firing, whereas D2 receptor activation increased input resistance. Current- and voltage-clamp experiments in projection neurons showed that D1 receptor activation enhanced excitability by modulating a 4-aminopyridine- and α-dendrotoxin-sensitive, slowly inactivating K+ current. Furthermore, DA and D1 receptor activation increased evoked firing in fast-spiking BLA interneurons. Consistent with a postsynaptic modulation of interneuron excitability, DA also increased the frequency of spontaneous inhibitory postsynaptic currents recorded in projection neurons without changing release of GABA. These data demonstrate that DA exerts direct effects on BLA projection neurons and indirect actions via modulation of interneurons that may work in concert to enhance the neuronal response to large, suprathreshold inputs, while suppressing weaker inputs.

Physiology, Pharmacology, and Topography of Cholinergic Neocortical Oscillations In Vitro

1997 ◽  
Vol 77 (5) ◽  
pp. 2427-2445 ◽  
Author(s):  
Heath S. Lukatch ◽  
M. Bruce Maciver
Keyword(s):  
Current Source ◽  
Brain Slices ◽  
Receptor Activation ◽  
Brain Regions ◽  
Oscillatory Activity ◽  
Cortical Layers ◽  
Eeg Activity ◽  
Layer 2

Lukatch, Heath S. and M. Bruce MacIver. Physiology, pharmacology, and topography of cholinergic neocortical oscillations in vitro. J. Neurophysiol. 77: 2427–2445, 1997. Rat neocortical brain slices generated rhythmic extracellular field [microelectroencephalogram (micro-EEG)] oscillations at theta frequencies (3–12 Hz) when exposed to pharmacological conditions that mimicked endogenous ascending cholinergic and GABAergic inputs. Use of the specific receptor agonist and antagonist carbachol and bicuculline revealed that simultaneous muscarinic receptor activation and γ-aminobutyric acid-A (GABAA)-mediated disinhibition werenecessary to elicit neocortical oscillations. Rhythmic activity was independent of GABAB receptor activation, but required intact glutamatergic transmission, evidenced by blockade or disruption of oscillations by 6-cyano-7-nitroquinoxaline-2,3-dione and (±)-2-amino-5-phosphonovaleric acid, respectively. Multisite mapping studies showed that oscillations were localized to areas 29d and 18b (Oc2MM) and parts of areas 18a and 17. Peak oscillation amplitudes occurred in layer 2/3, and phase reversals were observed in layers 1 and 5. Current source density analysis revealed large-amplitude current sinks and sources in layers 2/3 and 5, respectively. An initial shift in peak inward current density from layer 1 to layer 2/3 indicated that two processes underlie an initial depolarization followed by oscillatory activity. Laminar transections localized oscillation-generating circuitry to superficial cortical layers and sharp-spike-generating circuitry to deep cortical layers. Whole cell recordings identified three distinct cell types based on response properties during rhythmic micro-EEG activity: oscillation-on (theta-on) and -off (theta-off) neurons, and transiently depolarizing glial cells. Theta-on neurons displayed membrane potential oscillations that increased in amplitude with hyperpolarization (from −30 to −90 mV). This, taken together with a glutamate antagonist-induced depression of rhythmic micro-EEG activity, indicated that cholinergically driven neocortical oscillations require excitatory synaptic transmission. We conclude that under the appropriate pharmacological conditions, neocortical brain slices were capable of producing localized theta frequency oscillations. Experiments examining oscillation physiology, pharmacology, and topography demonstrated that neocortical brain slice oscillations share many similarities with the in vivo and in vitro theta EEG activity recorded in other brain regions.

Effect of cholinergic agonists on bulbospinal C1 neurons in rats

1997 ◽  
Vol 272 (1) ◽  
pp. R249-R258 ◽  
Author(s):  
D. Huangfu ◽  
M. Schreihofer ◽  
P. G. Guyenet
Keyword(s):  
Brain Slices ◽  
Reversal Potential ◽  
Input Resistance ◽  
Neonatal Rat ◽  
Ventrolateral Medulla ◽  
Cholinergic Agonists ◽  
Inward Currents ◽  
Tone Generation

Cholinergic inputs to the rostral ventrolateral medulla (RVLM) may contribute to sympathetic tone generation. The present study analyzes the response of RVLM neurons to cholinergic agonists. In chloralose-anesthetized rats iontophoresis of carbachol excited RVLM sympathoexcitatory neurons (+69% from resting level of 11.9 +/- 2 spikes/s; n = 28). This effect was reduced 85% by iontophoresis of methylatropine and abolished by intravenous scopolamine. Iontophoresis of nicotine or hexamethonium was ineffective. In contrast, most RVLM respiratory units were inhibited by carbachol. Whole cell recordings of bulbospinal RVLM neurons were made in neonatal rat brain slices (54 cells, 24 C1 adrenergic neurons). In current-clamp recordings (without tetrodotoxin) carbachol produced depolarization, increased postsynaptic potential frequency, and decreased input resistance. In voltage-clamp recording (-50 to -60 mV; 1 microM tetrodotoxin) carbachol produced inward current [50% effective concentration (EC50): 10 +/- 1 microM; 12.6 +/- 2 pA at 30 microM; n = 16] that persisted in low Ca2+/high Mg2+ (n = 6). Muscarine (30 microM) caused smaller inward currents (2.6 +/- 0.6 pA; n = 16). The carbachol-induced current was reduced 46% by 5 microM methylatropine (n = 15) and 84% by 200 microM hexamethonium (n = 9). The current was linear as a function of the holding potential (extrapolated reversal potential: -22 +/- 2 mV). In conclusion, carbachol exerts both pre- and postsynaptic effects on C1 and other putative sympathoexcitatory RVLM neurons. In vitro the postsynaptic effect of carbachol has a mixed nicotinic and muscarinic pharmacology. In vivo, iontophoretically applied carbachol produces muscarinic excitation of barosensitive RVLM neurons.

scholarly journals Dopamine D1 receptor activation drives plasticity in the songbird auditory pallium

2020 ◽  
Author(s):  
Matheus Macedo-Lima ◽  
Hannah M. Boyd ◽  
Luke Remage-Healey
Keyword(s):  
Vocal Learning ◽  
Receptor Activation ◽  
D1 Receptor ◽  
Auditory Neurons ◽  
Production Variability ◽  
Neuronal Types ◽  
Dopamine Signaling ◽  
Motor Production

AbstractVocal learning species must form and extensively hone associations between sounds and social contingencies. In songbirds, dopamine signaling guides song motor-production, variability, and motivation, but it is unclear how dopamine regulates fundamental auditory associations for learning new sounds. We hypothesized that dopamine regulates learning in the auditory pallium, in part by interacting with local neuroestradiol signaling. Here, we show that zebra finch auditory neurons frequently coexpress D1 receptor (D1R) protein, neuroestradiol-synthase, GABA, and parvalbumin. Auditory classical conditioning increased neuroplasticity gene induction in D1R-positive neurons. In vitro, D1R pharmacological activation reduced the amplitude of GABAergic and glutamatergic currents, and increased the latter’s frequency. In vivo, D1R activation reduced the firing of putative interneurons, increased the firing of putative excitatory neurons, and made both neuronal types unable to adapt to novel stimuli. Together, these data support the hypothesis that dopamine acting via D1Rs modulates learning and memory in the songbird sensory cortex.

scholarly journals Intracellular Properties of Deep-Layer Pyramidal Neurons in Frontal Eye Field of Macaque Monkeys

2021 ◽  
Vol 13 ◽  
Author(s):  
Charlotte Piette ◽  
Marie Vandecasteele ◽  
Clémentine Bosch-Bouju ◽  
Valérie Goubard ◽  
Vincent Paillé ◽  
...  
Keyword(s):  
Pyramidal Neurons ◽  
Deep Layer ◽  
Brain Slices ◽  
Cell Types ◽  
Frontal Eye Field ◽  
Visual Responses ◽  
Biophysical Properties ◽  
Eye Field

Although many details remain unknown, several positive statements can be made about the laminar distribution of primate frontal eye field (FEF) neurons with different physiological properties. Most certainly, pyramidal neurons in the deep layer of FEF that project to the brainstem carry movement and fixation signals but clear evidence also support that at least some deep-layer pyramidal neurons projecting to the superior colliculus carry visual responses. Thus, deep-layer neurons in FEF are functionally heterogeneous. Despite the useful functional distinctions between neuronal responses in vivo, the underlying existence of distinct cell types remain uncertain, mostly due to methodological limitations of extracellular recordings in awake behaving primates. To substantiate the functionally defined cell types encountered in the deep layer of FEF, we measured the biophysical properties of pyramidal neurons recorded intracellularly in brain slices issued from macaque monkey biopsies. Here, we found that biophysical properties recorded in vitro permit us to distinguish two main subtypes of regular-spiking neurons, with, respectively, low-resistance and low excitability vs. high-resistance and strong excitability. These results provide useful constraints for cognitive models of visual attention and saccade production by indicating that at least two distinct populations of deep-layer neurons exist.

scholarly journals In vivo imaging identifies temporal signature of D1 and D2 medium spiny neurons in cocaine reward

2016 ◽  
Vol 113 (10) ◽  
pp. 2726-2731 ◽  
Author(s):  
Erin S. Calipari ◽  
Rosemary C. Bagot ◽  
Immanuel Purushothaman ◽  
Thomas J. Davidson ◽  
Jordan T. Yorgason ◽  
...  
Keyword(s):  
Cell Types ◽  
Designer Drugs ◽  
Medium Spiny Neurons ◽  
Clear Understanding ◽  
Cocaine Exposure ◽  
Drug Seeking ◽  
Spiny Neurons ◽  
Key Factor ◽  
Contextual Associations

The reinforcing and rewarding properties of cocaine are attributed to its ability to increase dopaminergic transmission in nucleus accumbens (NAc). This action reinforces drug taking and seeking and leads to potent and long-lasting associations between the rewarding effects of the drug and the cues associated with its availability. The inability to extinguish these associations is a key factor contributing to relapse. Dopamine produces these effects by controlling the activity of two subpopulations of NAc medium spiny neurons (MSNs) that are defined by their predominant expression of either dopamine D1 or D2 receptors. Previous work has demonstrated that optogenetically stimulating D1 MSNs promotes reward, whereas stimulating D2 MSNs produces aversion. However, we still lack a clear understanding of how the endogenous activity of these cell types is affected by cocaine and encodes information that drives drug-associated behaviors. Using fiber photometry calcium imaging we define D1 MSNs as the specific population of cells in NAc that encodes information about drug associations and elucidate the temporal profile with which D1 activity is increased to drive drug seeking in response to contextual cues. Chronic cocaine exposure dysregulates these D1 signals to both prevent extinction and facilitate reinstatement of drug seeking to drive relapse. Directly manipulating these D1 signals using designer receptors exclusively activated by designer drugs prevents contextual associations. Together, these data elucidate the responses of D1- and D2-type MSNs in NAc to acute cocaine and during the formation of context–reward associations and define how prior cocaine exposure selectively dysregulates D1 signaling to drive relapse.

Ultrastructural observations on the in vitro cytoadherence of Plasmodium falciparum infected red blood cells

1990 ◽  
Vol 48 (3) ◽  
pp. 914-915
Author(s):  
D.J.P. Ferguson ◽  
A.R. Berendt ◽  
J. Tansey ◽  
K. Marsh ◽  
C.I. Newbold
Keyword(s):  
Plasmodium Falciparum ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Umbilical Vein ◽  
Cell Types ◽  
Amelanotic Melanoma ◽  
Cytoplasmic Process ◽  
Umbilical Vein Endothelial Cells

In human malaria, the most serious clinical manifestation is cerebral malaria (CM) due to infection with Plasmodium falciparum. The pathology of CM is thought to relate to the fact that red blood cells containing mature forms of the parasite (PRBC) cytoadhere or sequester to post capillary venules of various tissues including the brain. This in vivo phenomenon has been studied in vitro by examining the cytoadherence of PRBCs to various cell types and purified proteins. To date, three Ijiost receptor molecules have been identified; CD36, ICAM-1 and thrombospondin. The specific changes in the PRBC membrane which mediate cytoadherence are less well understood, but they include the sub-membranous deposition of electron-dense material resulting in surface deformations called knobs. Knobs were thought to be essential for cytoadherence, lput recent work has shown that certain knob-negative (K-) lines can cytoadhere. In the present study, we have used electron microscopy to re-examine the interactions between K+ PRBCs and both C32 amelanotic melanoma cells and human umbilical vein endothelial cells (HUVEC).We confirm previous data demonstrating that C32 cells possess numerous microvilli which adhere to the PRBC, mainly via the knobs (Fig. 1). In contrast, the HUVEC were relatively smooth and the PRBCs appeared partially flattened onto the cell surface (Fig. 2). Furthermore, many of the PRBCs exhibited an invagination of the limiting membrane in the attachment zone, often containing a cytoplasmic process from the endothelial cell (Fig. 2).

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