scholarly journals Bi-directional control of a prelimbic somatostatin microcircuit decreases binge alcohol consumption

2020 ◽  
Author(s):  
Nigel C. Dao ◽  
Dakota F. Brockway ◽  
Malini Suresh Nair ◽  
Nicole A. Crowley

ABSTRACTSomatostatin neurons have been implicated in a variety of neuropsychiatric disorders such as depression and anxiety, but their role in substance abuse disorders, including alcohol use disorder (AUD), is not fully characterized. Here we found that repeat cycles of alcohol binge drinking in the Drinking-in-the-Dark (DID) model led to hypoactivity of somatostatin (SST) neuronal in the prelimbic (PL) cortex by diminishing their action potential firing capacity and excitatory/inhibitory transmission dynamic. We examined their role in regulating alcohol consumption via bidirectional chemogenetic manipulation. Both hM3Dq-induced excitation and KORD-induced silencing of PL SST neurons paradoxically reduced alcohol binge drinking in males and females, with no effect on sucrose consumption. This effect is mediated directly via monosynaptic connection from SST neurons onto pyramidal neurons and indirectly via an intermediate GABAergic source. Optogenetic-assisted circuit mapping revealed that PL SST neurons preferentially synapse onto pyramidal neurons over other GABAergic populations in males, whereas SST neuron-mediated inhibition is balanced across cell types in females. Alcohol binge drinking disinhibits pyramidal neurons by augmenting SST neurons-mediated GABA release and synaptic strength onto other GABAergic populations. Together these data suggest substantial interaction between alcohol binge drinking and SST neurons inhibitory circuit in the PL, as well as provide evidence for these neurons as a potential therapeutic candidate for the treatment of alcohol use disorders, including binge drinking.

Author(s):  
Nigel C. Dao ◽  
Dakota F. Brockway ◽  
Malini Suresh Nair ◽  
Avery R. Sicher ◽  
Nicole A. Crowley

AbstractSomatostatin (SST) neurons have been implicated in a variety of neuropsychiatric disorders such as depression and anxiety, but their role in substance use disorders, including alcohol use disorder (AUD), is not fully characterized. Here, we found that repeated cycles of alcohol binge drinking via the Drinking-in-the-Dark (DID) model led to hypoactivity of SST neurons in the prelimbic (PL) cortex by diminishing their action potential firing capacity and excitatory/inhibitory transmission dynamic. We examined their role in regulating alcohol consumption via bidirectional chemogenetic manipulation. Both hM3Dq-induced excitation and KORD-induced silencing of PL SST neurons reduced alcohol binge drinking in males and females, with no effect on sucrose consumption. Alcohol binge drinking disinhibited pyramidal neurons by augmenting SST neurons-mediated GABA release and synaptic strength onto other GABAergic populations and reducing spontaneous inhibitory transmission onto pyramidal neurons. Pyramidal neurons additionally displayed increased intrinsic excitability. Direct inhibition of PL pyramidal neurons via hM4Di was sufficient to reduce alcohol binge drinking. Together these data revealed an SST-mediated microcircuit in the PL that modulates the inhibitory dynamics of pyramidal neurons, a major source of output to subcortical targets to drive reward-seeking behaviors and emotional response.


2012 ◽  
Vol 197 (2) ◽  
pp. 327-337 ◽  
Author(s):  
Arthur P.H. de Jong ◽  
Sabine K. Schmitz ◽  
Ruud F.G. Toonen ◽  
Matthijs Verhage

Different regulatory principles influence synaptic coupling between neurons, including positional principles. In dendrites of pyramidal neurons, postsynaptic sensitivity depends on synapse location, with distal synapses having the highest gain. In this paper, we investigate whether similar rules exist for presynaptic terminals in mixed networks of pyramidal and dentate gyrus (DG) neurons. Unexpectedly, distal synapses had the lowest staining intensities for vesicular proteins vGlut, vGAT, Synaptotagmin, and VAMP and for many nonvesicular proteins, including Bassoon, Munc18, and Syntaxin. Concomitantly, distal synapses displayed less vesicle release upon stimulation. This dependence of presynaptic strength on dendritic position persisted after chronically blocking action potential firing and postsynaptic receptors but was markedly reduced on DG dendrites compared with pyramidal dendrites. These data reveal a novel rule, independent of neuronal activity, which regulates presynaptic strength according to dendritic position, with the strongest terminals closest to the soma. This gradient is opposite to postsynaptic gradients observed in pyramidal dendrites, and different cell types apply this rule to a different extent.


2013 ◽  
Vol 110 (1) ◽  
pp. 221-229 ◽  
Author(s):  
Jonathan Dilgen ◽  
Hugo A. Tejeda ◽  
Patricio O'Donnell

Although interactions between the amygdala and prefrontal cortex (PFC) are critical for emotional guidance of behavior, the manner in which amygdala affects PFC function is not clear. Whereas basolateral amygdala (BLA) output neurons exhibit many characteristics associated with excitatory neurotransmission, BLA stimulation typically inhibits PFC cell firing. This apparent discrepancy could be explained if local PFC inhibitory interneurons were activated by BLA inputs. Here, we used in vivo juxtacellular and intracellular recordings in anesthetized rats to investigate whether BLA inputs evoke feedforward inhibition in the PFC. Juxtacellular recordings revealed that BLA stimulation evoked action potentials in PFC interneurons and silenced most pyramidal neurons. Intracellular recordings from PFC pyramidal neurons showed depolarizing postsynaptic potentials, with multiple components evoked by BLA stimulation. These responses exhibited a relatively negative reversal potential (Erev), suggesting the contribution of a chloride component. Intracellular administration or pressure ejection of the GABA-A antagonist picrotoxin resulted in action-potential firing during the BLA-evoked response, which had a more depolarized Erev. These results suggest that BLA stimulation engages a powerful inhibitory mechanism within the PFC mediated by local circuit interneurons.


Author(s):  
Minkyung Kang ◽  
Ari Min ◽  
Haeyoung Min

Gender differences in alcohol use have narrowed over the decades. This study aimed to explore changes in alcohol consumption patterns between 2007 and 2016 to identify gender convergence in alcohol use in Korea. Data from the Korea National Health and Nutrition Examination Survey were used. For all respondents (41,662 girls/women and 32,041 boys/men) aged ≥12 years, lifetime drinking, current drinking, age of drinking onset, heavy alcohol use, and binge drinking were analyzed. Gender differences in heavy alcohol use and binge drinking decreased from 2007 to 2016 (p = 0.001 and p < 0.001, respectively). The prevalence of heavy alcohol use and binge drinking decreased in boys/men (67.5% to 63.9%, p = 0.001; 63.4% to 60.9%, p = 0.001, respectively), but not in girls/women (50.2% to 50.4%, p = 0.279; 30.6% to 32.0%, p = 0.994, respectively). The proportion of lifetime abstainers decreased among both girls/women (24.3% to 19.1%, p < 0.001) and boys/men (12.1% to 9.7%, p = 0.01). In girls/women, the mean age of drinking onset decreased (from 24.1 to 23.6 years, p = 0.017); however, in boys/men, significant changes were not observed (from 18.9 to 18.7 years, p = 0.307). Healthcare providers should be aware of the growing health risks resulting from increased unhealthy alcohol use in women and develop gender-specific preventive interventions.


2005 ◽  
Vol 93 (2) ◽  
pp. 843-852 ◽  
Author(s):  
Gergana Hadjilambreva ◽  
Eilhard Mix ◽  
Arndt Rolfs ◽  
Jana Müller ◽  
Ulf Strauss

The immunomodulatory cytokine interferon-β (IFN-β) is used in the treatment of autoimmune diseases such as multiple sclerosis. However, the effect of IFN-β on neuronal functions is currently unknown. Intracellular recordings were conducted on somatosensory neurons of neocortical layers 2/3 and 5 exposed to IFN-β. The excitability of neurons was increased by IFN-β (10–10,000 U/ml) in two kinetically distinct, putatively independent manners. First IFN-β reversibly influenced the subthreshold membrane response by raising the membrane resistance RM 2.5-fold and the membrane time constant τ 1.7-fold dose-dependently. The effect required permanent exposure to IFN-β and was reduced in magnitude if the extracellular K+ was lowered. However, the membrane response to IFN-β in the subthreshold range was prevented by ZD7288 (a specific blocker of Ih) but not by Ni2+, carbachol, or bicuculline, pointing to a dependence on an intact Ih. Second, IFN-β enhanced the rate of action potential firing. This effect was observed to develop for >1 h when the cell was exposed to IFN-β for 5 min or >5 min and showed no reversibility (≤210 min). Current-discharge ( F-I) curves revealed a shift (prevented by bicuculline) as well as an increase in slope (prevented by carbachol and Ni2+). Layer specificity was not observed with any of the described effects. In conclusion, IFN-β influences the neuronal excitability in neocortical pyramidal neurons in vitro, especially under conditions of slightly increased extracellular K+. Our blocker experiments indicate that changes in various ionic conductances with different voltage dependencies cause different IFN-β influences on sub- and suprathreshold behavior, suggesting a more general intracellular process induced by IFN-β.


2019 ◽  
Author(s):  
Antara Das ◽  
Bingyao Zhu ◽  
Yunyao Xie ◽  
Lisha Zeng ◽  
An T. Pham ◽  
...  

AbstractAdvances in genome sequencing have identified over 1300 mutations in the SCN1A sodium channel gene that result in genetic epilepsies. However, how individual mutations within SCN1A produce seizures remains elusive for most mutations. Previous work from our lab has shown that the K1270T (KT) mutation, which is linked to GEFS+ (Genetic Epilepsy with Febrile Seizure plus) in humans, causes reduced firing of GABAergic neurons in a Drosophila knock-in model. To examine the effect of this mutation in mammals, we introduced the equivalent KT mutation into the mouse Scn1a (Scn1aKT) gene using CRISPR/Cas9. Mouse lines carrying this mutation were examined in two widely used genetic backgrounds, C57BL/6NJ and 129×1/SvJ. In both backgrounds, homozygous mutants had spontaneous seizures and died by postnatal day 23. There was no difference in the lifespan of mice heterozygous for the mutation in either background when compared to wild-type littermates up to 6 months. Heterozygous mutants had heat-induced seizures at ~42 deg. Celsius, a temperature that did not induce seizures in wild-type littermates. In acute hippocampal slices, current-clamp recordings revealed a significant depolarized shift in action potential threshold and reduced action potential amplitude in parvalbumin-expressing inhibitory interneurons in Scn1aKT/+ mice. There was no change in the firing properties of excitatory CA1 pyramidal neurons. Our results indicate that Scn1aKT/+ mice develop seizures, and impaired action potential firing of inhibitory interneurons in Scn1aKT/+ mice may produce hyperexcitability in the hippocampus.


2021 ◽  
Vol 15 ◽  
Author(s):  
Alison S. Walker ◽  
Benjamin K. Raliski ◽  
Dat Vinh Nguyen ◽  
Patrick Zhang ◽  
Kate Sanders ◽  
...  

Voltage imaging with fluorescent dyes affords the opportunity to map neuronal activity in both time and space. One limitation to imaging is the inability to image complete neuronal networks: some fraction of cells remains outside of the observation window. Here, we combine voltage imaging, post hoc immunocytochemistry, and patterned microisland hippocampal culture to provide imaging of complete neuronal ensembles. The patterned microislands completely fill the field of view of our high-speed (500 Hz) camera, enabling reconstruction of the spiking patterns of every single neuron in the network. Cultures raised on microislands are similar to neurons grown on coverslips, with parallel developmental trajectories and composition of inhibitory and excitatory cell types (CA1, CA3, and dentate granule cells, or DGC). We calculate the likelihood that action potential firing in one neuron triggers action potential firing in a downstream neuron in a spontaneously active network to construct a functional connection map of these neuronal ensembles. Importantly, this functional map indicates preferential connectivity between DGC and CA3 neurons and between CA3 and CA1 neurons, mimicking the neuronal circuitry of the intact hippocampus. We envision that patterned microislands, in combination with voltage imaging and methods to classify cell types, will be a powerful method for exploring neuronal function in both healthy and disease states. Additionally, because the entire neuronal network is sampled simultaneously, this strategy has the power to go further, revealing all functional connections between all cell types.


1999 ◽  
Vol 81 (5) ◽  
pp. 2347-2359 ◽  
Author(s):  
Antonio G. Paolini ◽  
Graeme M. Clark

Intracellular responses of onset chopper neurons in the ventral cochlear nucleus to tones: evidence for dual-component processing. The ventral cochlear nucleus (VCN) contains a heterogeneous collection of cell types reflecting the multiple processing tasks undertaken by this nucleus. This in vivo study in the rat used intracellular recordings and dye filling to examine membrane potential changes and firing characteristics of onset chopper (OC) neurons to acoustic stimulation (50 ms pure tones, 5 ms r/f time). Stable impalements were made from 15 OC neurons, 7 identified as multipolar cells. Neurons responded to characteristic frequency (CF) tones with sustained depolarization below spike threshold. With increasing stimulus intensity, the depolarization during the initial 10 ms of the response became peaked, and with further increases in intensity the peak became narrower. Onset spikes were generated during this initial depolarization. Tones presented below CF resulted in a broadening of this initial depolarizing component with high stimulus intensities required to initiate onset spikes. This initial component was followed by a sustained depolarizing component lasting until stimulus cessation. The amplitude of the sustained depolarizing component was greatest when frequencies were presented at high intensities below CF resulting in increased action potential firing during this period when compared with comparable high intensities at CF. During the presentation of tones at or above the high-frequency edge of a cell’s response area, hyperpolarization was evident during the sustained component. The presence of hyperpolarization and the differences seen in the level of sustained depolarization during CF and off CF tones suggests that changes in membrane responsiveness between the initial and sustained components may be attributed to polysynaptic inhibitory mechanisms. The dual-component processing resulting from convergent auditory nerve excitation and polysynaptic inhibition enables OC neurons to respond in a unique fashion to intensity and frequency features contained within an acoustic stimulus.


2012 ◽  
Vol 303 (9) ◽  
pp. E1107-E1116 ◽  
Author(s):  
Balrik Kailey ◽  
Martijn van de Bunt ◽  
Stephen Cheley ◽  
Paul R. Johnson ◽  
Patrick E. MacDonald ◽  
...  

Somatostatin-14 (SST) inhibits insulin and glucagon secretion by activating G protein-coupled somatostatin receptors (SSTRs), of which five isoforms exist (SSTR1–5). In mice, the effects on pancreatic β-cells are mediated by SSTR5, whereas α-cells express SSTR2. In both cell types, SSTR activation results in membrane hyperpolarization and suppression of exocytosis. Here, we examined the mechanisms by which SST inhibits secretion from human β- and α-cells and the SSTR isoforms mediating these effects. Quantitative PCR revealed high expression of SSTR2, with lower levels of SSTR1, SSTR3, and SSTR5, in human islets. Immunohistochemistry showed expression of SSTR2 in both β- and α-cells. SST application hyperpolarized human β-cells and inhibited action potential firing. The membrane hyperpolarization was unaffected by tolbutamide but antagonized by tertiapin-Q, a blocker of G protein-gated inwardly rectifying K+ channels (GIRK). The effect of SST was mimicked by an SSTR2-selective agonist, whereas a SSTR5 agonist was marginally effective. SST strongly (>70%) reduced depolarization-evoked exocytosis in both β- and α-cells. A slightly weaker inhibition was observed in both cell types after SSTR2 activation. SSTR3- and SSTR1-selective agonists moderately reduced the exocytotic responses in β- and α-cells, respectively, whereas SSTR4- and SSTR5-specific agonists were ineffective. SST also reduced voltage-gated P/Q-type Ca2+ currents in β-cells, but normalization of Ca2+ influx to control levels by prolonged depolarizations only partially restored exocytosis. We conclude that SST inhibits secretion from both human β- and α-cells by activating GIRK and suppressing electrical activity, reducing P/Q-type Ca2+ currents, and directly inhibiting exocytosis. These effects are mediated predominantly by SSTR2 in both cell types.


2019 ◽  
Vol 121 (3) ◽  
pp. 773-784 ◽  
Author(s):  
Timothy W. Church ◽  
Jon T. Brown ◽  
Neil V. Marrion

Action potential firing in hippocampal pyramidal neurons is regulated by generation of an afterhyperpolarization (AHP). Three phases of AHP are recognized, with the fast AHP regulating action potential firing at the onset of a burst and the medium and slow AHPs supressing action potential firing over hundreds of milliseconds and seconds, respectively. Activation of β-adrenergic receptors suppresses the slow AHP by a protein kinase A-dependent pathway. However, little is known regarding modulation of the medium AHP. Application of the selective β-adrenergic receptor agonist isoproterenol suppressed both the medium and slow AHPs evoked in rat CA1 hippocampal pyramidal neurons recorded from slices maintained in organotypic culture. Suppression of the slow AHP was mimicked by intracellular application of cAMP, with the suppression of the medium AHP by isoproterenol still being evident in cAMP-dialyzed cells. Suppression of both the medium and slow AHPs was antagonized by the β-adrenergic receptor antagonist propranolol. The effect of isoproterenol to suppress the medium AHP was mimicked by two β3-adrenergic receptor agonists, BRL37344 and SR58611A. The medium AHP was mediated by activation of small-conductance calcium-activated K+ channels and deactivation of H channels at the resting membrane potential. Suppression of the medium AHP by isoproterenol was reduced by pretreating cells with the H-channel blocker ZD7288. These data suggest that activation of β3-adrenergic receptors inhibits H channels, which suppresses the medium AHP in CA1 hippocampal neurons by utilizing a pathway that is independent of a rise in intracellular cAMP. This finding highlights a potential new target in modulating H-channel activity and thereby neuronal excitability. NEW & NOTEWORTHY The noradrenergic input into the hippocampus is involved in modulating long-term synaptic plasticity and is implicated in learning and memory. We demonstrate that activation of functional β3-adrenergic receptors suppresses the medium afterhyperpolarization in hippocampal pyramidal neurons. This finding provides an additional mechanism to increase action potential firing frequency, where neuronal excitability is likely to be crucial in cognition and memory.


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