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We previously reported that enhanced corticotropin-releasing factor (CRF) signaling in the bed nucleus of the stria terminalis (BNST) caused the aversive responses during acute pain and suppressed the brain reward system during chronic pain. However, it remains to be examined whether chronic pain alters the excitability of CRF neurons in the BNST. In this study we investigated the chronic pain-induced changes in excitability of CRF-expressing neurons in the oval part of the BNST (ovBNSTCRF neurons) by whole-cell patch-clamp electrophysiology. CRF-Cre; Ai14 mice were used to visualize CRF neurons by tdTomato. Electrophysiological recordings from brain slices prepared from a mouse model of neuropathic pain revealed that rheobase and firing threshold were significantly decreased in the chronic pain group compared with the sham-operated control group. Firing rate of the chronic pain group was higher than that of the control group. These data indicate that chronic pain elevated neuronal excitability of ovBNSTCRF neurons. [ABSTRACT FROM AUTHOR]

Aim: Our previous studies showed that exposure to acute restraint stress enhanced cocaine‐induced conditioned place preference (cocaine‐CPP) and suggested the possibility that co‐activation of adrenergic transmission boosts the increase in medial prefrontal cortex (mPFC) neuronal activity by the activation of dopaminergic transmission. To examine this possibility, the effects of the co‐treatment with dopamine (DA) and noradrenaline (NA) on mPFC neurons were compared with those of treatment with DA alone using whole‐cell patch‐clamp recordings. Methods: The effects of DA alone and a mixture of DA and NA on the membrane potentials and spontaneous excitatory postsynaptic currents (sEPSCs) were examined by electrophysiological recordings of mPFC pyramidal neurons in brain slices of male Sprague Dawley rats. Extracellular DA and NA levels in the mPFC during and after restraint stress exposure were also examined by in vivo microdialysis. Results: Dopamine significantly produced depolarizing effects on mPFC neurons and tended to increase sEPSC frequency. Co‐administration of NA with DA produced stronger depolarizing effects and significantly increased sEPSC frequency. The findings suggest that the additional depolarizing effect of NA on DA‐responsive neurons, rather than the excitation of DA‐nonresponsive neurons by NA, contributes to the stronger effect of co‐treatment of NA with DA. Conclusion: The present study suggests that NA released by restraint stress exposure cooperates with DA to stimulate DA‐responsive neurons in the mPFC, thereby causing the stress‐induced enhancement of cocaine‐CPP. [ABSTRACT FROM AUTHOR]

The bed nucleus of the stria terminalis (BNST) and the central amygdala (CeA) comprise a forebrain unit that has been described as the "extended amygdala". These two nuclei send dense projections to each other and have been implicated in the regulation of negative emotional states, including anxiety and fear. The present study employed an optogenetic technique to examine whether stimulation of CeA‐projecting dorsolateral BNST (dlBNST) neuron terminals would influence anxiety‐like behaviors in male Sprague‐Dawley rats. Photostimulation of CeA‐projecting dlBNST neuron terminals produced anxiogenic effects in an elevated plus maze test. This finding is inconsistent with previous reports showing that optogenetic stimulation of BNST neurons projecting to the lateral hypothalamus (LH) and ventral tegmental area (VTA) produces anxiolytic rather than anxiogenic effects. To address this issue, electrophysiological analyses were conducted to characterize dlBNST neurons projecting to the CeA, LH, and VTA. dlBNST neurons can be electrophysiologically classified into three distinct cell types (types I–III) according to their responses to depolarizing and hyperpolarizing current injections. Whole‐cell patch‐clamp recordings revealed that more than 60% of the CeA‐projecting dlBNST neurons were type II, whereas approximately 80% of the LH‐ and VTA‐projecting dlBNST neurons were type III. These electrophysiological results will help elucidate the mechanisms underlying the heterogeneity of BNST neurons during the regulation of anxiety‐like behaviors. Stimulation of the neural pathway from the bed nucleus of the stria terminalis (BNST) to the central amygdala (CeA) produced anxiogenic effects, that is in contrast to the report that stimulation of lateral hypothalamus (LH)‐ and ventral tegmental area (VTA)‐projecting BNST neurons produces anxiolytic ones. Electrophysiological analyses demonstrated different proportions of cell types between CeA‐projecting (more than 60% are type II) and LH/VTA‐projecting (about 80% are type III) BNST neurons. [ABSTRACT FROM AUTHOR]

Pain is a complex experience involving sensory and affective components. Although the neuronal mechanisms underlying the sensory component of pain have been extensively studied, those underlying its affective component have yet to be elucidated. Recently, we reported that corticotrophin-releasing factor ( CRF)-induced depolarization in type II neurons within the dorsolateral bed nucleus of the stria terminalis (dl BNST) is critical for pain-induced aversive responses in rats. However, the intracellular signaling underlying the excitatory effects of CRF and the contribution of such signaling to the induction of pain-induced aversion remain unclear. In the present study, we addressed these issues by conducting whole-cell patch-clamp recordings in rat brain slices and by undertaking behavioral pharmacological analyses. Intracellular perfusion of protein kinase A ( PKA) inhibitor Rp-cyclic adenosine monophosphorothioate (Rp- cAMPS) or KT5720 suppressed the excitatory effects of CRF in type II dl BNST neurons, and bath application of Rp- cAMPS also suppressed it. In addition, bath application of forskolin, an adenylate cyclase ( AC) activator, mimicked the effects of CRF, and pretreatment with forskolin diminished the excitatory effects of CRF. Furthermore, a conditioned place aversion ( CPA) test showed that co-administration of Rp- cAMPS with CRF into the dl BNST suppressed CRF-induced CPA. Intra-dl BNST injection of Rp- cAMPS also suppressed pain-induced CPA. These results suggest that CRF increases excitability of type II dl BNST neurons through activation of the AC- cAMP- PKA pathway, thereby causing pain-induced aversive responses. The present findings shed light on the neuronal mechanisms underlying the negative affective component of pain and may provide therapeutic targets for treating intractable pain accompanied by psychological factors. [ABSTRACT FROM AUTHOR]

Paternal behavior is not innate but arises through social experience. After mating and becoming fathers, male mice change their behavior toward pups from infanticide to paternal care. However, the precise brain areas and circuit mechanisms connecting these social behaviors are largely unknown. Here we demonstrated that the c-Fos expression pattern in the four nuclei of the preoptic-bed nuclei of stria terminalis ( BST) region could robustly discriminate five kinds of previous social behavior of male mice (parenting, infanticide, mating, inter-male aggression, solitary control). Specifically, neuronal activation in the central part of the medial preoptic area ( cMPOA) and rhomboid nucleus of the BST ( BSTrh) retroactively detected paternal and infanticidal motivation with more than 95% accuracy. Moreover, cMPOA lesions switched behavior in fathers from paternal to infanticidal, while BSTrh lesions inhibited infanticide in virgin males. The projections from cMPOA to BSTrh were largely GABAergic. Optogenetic or pharmacogenetic activation of cMPOA attenuated infanticide in virgin males. Taken together, this study identifies the preoptic- BST nuclei underlying social motivations in male mice and reveals unexpected complexity in the circuit connecting these nuclei. [ABSTRACT FROM AUTHOR]

Recent findings implicate the central lateral amygdala (CeL) in conditioned fear. Indeed, CeL contains neurons exhibiting positive (CeL-On) or negative (CeL-Off) responses to fear-inducing conditioned stimuli (CSs). In mice, these cells differ in their expression of protein kinase Cδ (PKCδ) and physiological properties. CeL-Off cells are PKCδ+and late firing (LF), whereas CeL-On cells are PKCδ−and express a regular-spiking (RS) or low-threshold bursting (LTB) phenotype. However, the scarcity of LF cells in rats raises questions about the correspondence between the organization of CeL in mice and rats. Therefore, we studied the PKCδ expression, morphological properties, synaptic responsiveness, and fear conditioning-induced plasticity of rat CeL neurons. No PKCδ+LF cells were encountered, but ≈20–25% of RS and LTB neurons were PKCδ+. Compared with RS neurons, a higher proportion of LTB cells projected to central medial amygdala (CeM) and they had fewer primary dendritic branches, yet the amplitude of excitatory postsynaptic potentials (EPSPs) evoked by lateral amygdala (LA) stimulation was similar in RS and LTB cells. In contrast, LA-evoked inhibitory postsynaptic potentials (IPSPs) had a higher amplitude in LTB than RS neurons. Finally, fear conditioning did not induce plasticity at LA inputs to RS or LTB neurons. These findings point to major species differences in the organization of CeL. Since rat LTB cells are subjected to stronger feedforward inhibition, they are more likely to exhibit inhibitory CS responses than RS cells. This is expected to cause a disinhibition of CeM fear output neurons and therefore an increase in fear expression. [ABSTRACT FROM AUTHOR]

The lateral nucleus (LA) is the input station of the amygdala for information about conditioned stimuli (CSs), whereas the medial sector of the central nucleus (CeM) is the output region that contributes most amygdala projections to brainstem fear effectors. However, there are no direct links between LA and CeM. As the main target of LA and with its strong projection to CeM, the basomedial amygdala (BM) constitutes a good candidate to bridge this gap. Consistent with this notion, it was reported that combined posttraining lesions of the basal nuclei [BM plus basolateral nucleus (BL)] abolish conditioned fear responses, whereas selective BL inactivation does not. Thus, we examined the relative contribution of BM and BL to conditioned fear using unit recordings and inactivation with muscimol microinfusions in rats. Approximately 30% ofBMand BL neurons acquired robust responses to auditory CSs predicting footshocks. While most BL cells stopped firing at CS offset,BMresponses typically outlasted the CS byβ40 s, paralleling the persistence of conditioned fear after the CS. This observation suggests that BM neurons are not passive relays of rapidly adapting LA inputs about the CS. Surprisingly, independent inactivation of either BM or BL with muscimol did not cause a reduction of conditioned freezing even though an extinction recall deficit was seen the next day. In contrast, combinedBL-BMinactivation did. Overall, there results support the notion that the basal nuclei are involved in conditioned fear expression and extinction but that there is functional redundancy between them. [ABSTRACT FROM AUTHOR]

Intercalated (ITC) amygdala neurons are thought to play a critical role in the extinction of conditioned fear. However, several factors hinder progress in studying ITC contributions to extinction. First, although extinction is usually studied in rats and mice, most ITC investigations were performed in guinea pigs or cats. Thus it is unclear whether their connectivity is similar across species. Second, we lack criteria to identify ITC cells on the basis of their discharge pattern. As a result, key predictions of ITC extinction models remain untested. Among these, ITC cells were predicted to be strongly excited by infralimbic inputs, explaining why infralimbic inhibition interferes with extinction. To study the connectivity of ITC cells, we labeled them with neurobiotin during patch recordings in slices of the rat amygdala. This revealed that medially located ITC cells project topographically to the central nucleus and to other ITC clusters located more ventrally. To study the infralimbic responsiveness of ITC cells, we performed juxtacellular recording and labeling of amygdala cells with neurobiotin in anesthetized rats. All ITC cells were orthodromically responsive to infralimbic stimuli, and their responses usually consisted of high-frequency (~350 Hz) trains of four to six spikes, a response pattern never seen in neighboring amygdala nuclei. Overall, our results suggest that the connectivity of ITC cells is conserved across species and that ITC cells are strongly responsive to infralimbic stimuli, as predicted by extinction models. The unique response pattern of ITC cells to infralimbic stimuli can now be used to identify them in fear conditioning experiments. [ABSTRACT FROM AUTHOR]

Anxiety disorders such as post-traumatic stress are characterized by an impaired ability to learn that cues previously associated with danger no longer represent a threat. However, the mechanisms underlying fear extinction remain unclear. We found that fear extinction in rats was associated with increased levels of synaptic inhibition in fear output neurons of the central amygdala (CEA). This increased inhibition resulted from a potentiation of fear input synapses to GABAergic intercalated amygdala neurons that project to the CEA. Enhancement of inputs to intercalated cells required prefrontal activity during extinction training and involved an increased transmitter release probability coupled to an altered expression profile of ionotropic glutamate receptors. Overall, our results suggest that intercalated cells constitute a promising target for pharmacological treatment of anxiety disorders. [ABSTRACT FROM AUTHOR]

Neurotensin receptor type-1 (Ntsr1) is the main receptor subtype that underlies neurotensin (NT)-mediated modulation of the dopamine (DA) system. Although NT and DA coexist in the basolateral nucleus of the amygdala (BLA), the function of Ntsr1 in the amygdala is not well characterized. In the present study, we utilized Ntsr1 knockout (Ntsr1-KO) mice to examine the role of Ntsr1 in the amygdala. In acute brain slices of Ntsr1-KO mice, synaptic currents elicited in BLA pyramidal neurons by electrical stimulation of the lateral nucleus of the amygdala (LA) were greatly potentiated by tetanic stimulation (BLA-long-term potentiation (LTP)). Such potentiation was not evident in pyramidal neurons of wild-type mice. In the presence of an antagonist of Ntsr1, SR48692, BLA-LTP was consistently observed in the neurons of wild-type mice, suggesting that both inherited deletion and acute pharmacological blockade of Ntsr1 induce BLA-LTP. BLA-LTP in Ntsr1-KO mice was impaired by sulpiride, a DA D2-like receptor antagonist. Conversely, quinpirole, a D2-like receptor agonist, induced pronounced BLA-LTP in wild-type mice, suggesting the upregulation of D2-like receptor activity in Ntsr1-KO mice. The ratio of NMDA receptor-mediated to non-NMDA receptor-mediated synaptic currents in Ntsr1-KO mouse BLA neurons was approximately double that measured in wild-type mouse neurons. Furthermore, quinpirole potentiated NMDA receptor-mediated synaptic currents in the BLA of wild-type mice. These results suggest that, without Ntsr1, synaptic responses from the LA to BLA pyramidal neurons undergo LTP in response to tetanus stimulation through facilitation of D2-like receptor-induced activation of NMDA receptors.Neuropsychopharmacology (2008) 33, 3135–3145; doi:10.1038/npp.2008.38; published online 19 March 2008 [ABSTRACT FROM AUTHOR]

Loss-of-function mutations of the parkin gene causes an autosomal recessive juvenile-onset form of Parkinson's disease (AR-JP). Parkin was shown to function as a RING-type E3 ubiquitin protein ligase. However, the function of parkin in neuronal cells remains elusive. Here, we show that expression of parkin-potentiated adenosine triphosphate (ATP)-induced currents that result from activation of the P2X receptors which are widely distributed in the brain and involved in neurotransmission. ATP-induced inward currents were measured in mock-, wild-type or mutant (T415N)-parkin-transfected PC12 cells under the conventional whole-cell patch clamp configuration. The amplitude of ATP-induced currents was significantly greater in wild-type parkin-transfected cells. However, the immunocytochemical study showed no apparent increase in the number of P2X receptors or in ubiquitin levels. The increased currents were attenuated by inhibition of cAMP-dependent protein kinase (PKA) but not protein kinase C (PKC) or Ca2+ and calmodulin-dependent protein kinase (CaMKII). ATP-induced currents were also regulated by phosphatases and cyclin-dependent protein kinase 5 (CDK5) via dopamine and cyclic AMP-regulated phosphoprotein (DARPP-32), though the phosphorylation at Thr-34 and Thr-75 were unchanged or rather attenuated. We also tried to investigate the effect of α-synuclein, a substrate of parkin and also forming Lysine 63-linked multiubiquitin chains. Expression of α-synuclein did not affect the amplitude of ATP-induced currents. Our finding provides the evidence for a relationship between parkin and a neurotransmitter receptor, suggesting that parkin may play an important role in synaptic activity. J. Cell. Physiol. 209: 172–182, 2006. © 2006 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Mammalian neuronal cells abundantly express a de-ubiquitinating isozyme, ubiquitin carboxy-terminal hydrolase L1 (UCH L1). Loss of UCH L1 function causes dying-back type of axonal degeneration. However, the function of UCH L1 in neuronal cells remains elusive. Here we show that overexpression of UCH L1 potentiated ATP-induced currents due to the activation of P2X receptors that are widely distributed in the brain and involved in various biological activities including neurosecretion. ATP-induced inward currents were measured in mock-, wild-type or mutant (C90S)-UCH L1-transfected PC12 cells under the conventional whole-cell patch clamp configuration. The amplitude of ATP-induced currents was significantly greater in both wild-type and C90S UCH L1-transfected cells, suggesting that hydrolase activity was not involved but increased level of mono-ubiquitin might play an important role. The increased currents were dependent on cAMP-dependent protein kinase (PKA) and Ca2+ and calmodulin-dependent protein kinase (CaMKII) but not protein kinase C. In addition, ATP-induced currents were likely to be modified via dopamine and cyclic AMP-regulated phosphoprotein (DARPP-32) that is regulated by PKA and phosphatases. Our finding shows the first evidence that there is a relationship between UCH L1 and neurotransmitter receptor, suggesting that UCH L1 may play an important role in synaptic activity. [ABSTRACT FROM AUTHOR]

The comorbidities of depression and chronic pain have long been recognized in the clinic, and several preclinical studies have demonstrated depression-like behaviors in animal models of chronic pain. These findings suggest a common neuronal basis for depression and chronic pain. Recently, we reported that the mesolimbic dopaminergic system was tonically suppressed during chronic pain by enhanced inhibitory synaptic inputs to neurons projecting from the dorsolateral bed nucleus of the stria terminalis (dlBNST) to the ventral tegmental area (VTA), suggesting that tonic suppression of the mesolimbic dopaminergic system by this neuroplastic change may be involved in chronic pain-induced depression-like behaviors. In this study, we hypothesized that inhibitory synaptic inputs to VTA-projecting dlBNST neurons are also enhanced in animal models of depression, thereby suppressing the mesolimbic dopaminergic system. To test this hypothesis, we performed whole-cell patch-clamp electrophysiology using brain slices prepared from rats exposed to chronic mild stress (CMS), a widely used animal model of depression. The results showed a significant enhancement in the frequency of spontaneous inhibitory postsynaptic currents in VTA-projecting dlBNST neurons in the CMS group compared with the no stress group. The findings revealed enhanced inhibitory synaptic inputs to VTA-projecting dlBNST neurons in this rat model of depression, suggesting that this neuroplastic change is a neuronal mechanism common to depression and chronic pain that causes dysfunction of the mesolimbic dopaminergic system, thereby inducing depression-like behaviors. [ABSTRACT FROM AUTHOR]

Speculating that the |$ud$| diquark with spin 0 has a similar mass to the constituent |$s$| quark, we introduce a symmetry between the |$s$| quark and the |$\overline{ud}$| diquark. Constructing an algebra for this symmetry, we regard a triplet of the |$s$| quarks with spin up and down and the |$\overline{ud}$| diquark with spin 0 as a fundamental representation of this algebra. We further build higher representations constructed by direct products of the fundamental representations. We propose assignments of hadrons to the multiples of this algebra. We find in particular that |$\{D_{s}, D_{s}^{*}, \Lambda_{c}\}$|⁠ , |$\{\eta_{s}, \phi, \Lambda, f_{0}(1370)\}$|⁠ , and |$\{\Omega_{c}, T_{sc}\}$| form a triplet, a nonet, and a quintet, respectively, where |$T_{sc}$| is a genuine tetraquark meson composed of |$\overline{ud}sc$|⁠. We also find a mass relation between them by introducing symmetry breaking due to the mass difference between the |$s$| quark and the |$\overline{ud}$| diquark. The masses of the possible tetraquarks |$\overline{ud}sc$| and |$\overline{ud}sb$| are estimated from the symmetry breaking and the masses of |$\Omega_{c}$| and |$\Omega_{b}$| to be 2.942 GeV and 6.261 GeV, respectively. [ABSTRACT FROM AUTHOR]