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Hiroki Toyoda
The insular cortex plays essential roles in nicotine addiction. However, much is still unknown about its cellular and synaptic mechanisms responsible for nicotine addiction. We have previously shown that in layer 5 pyramidal neurons of the mouse insular cortex, activation of nicotinic acetylcholine receptors (nAChRs) suppresses synaptic potentiation through enhancing GABAergic synaptic transmission although it enhances both glutamatergic and GABAergic synaptic transmission. In the present study, we examined whether dopamine receptors might contribute to the nicotine-induced inhibition of synaptic potentiation...
February 14, 2019: Synapse
Hua Jia, Ying Wang, Jiao Chen, Jun-Ping Li, Huai-Qin Han, Xiao-Jie Tong, Zhong-Yi He, Wen-Zhi Ma
Peripheral nerve gaps often lead to interrupted innervation, manifesting as severe sensory and motor dysfunctions. The repairs of the nerve injuries have not achieved satisfactory curative effects in clinic. The transplantation of bone marrow stromal cells (BMSCs)-laden acellular nerve xenografts (ANX) has been proven more effective than the acellular nerve allografting. Besides, granulocyte-colony stimulating factor (G-CSF) can inhibit inflammation and apoptosis, and thus is conducive to the microenvironmental improvement of axonal regeneration...
February 14, 2019: Synapse
Peter Koppensteiner, Christopher Galvin, Ipe Ninan
Fear extinction, an inhibitory learning that suppresses a previously learned fear memory, is diminished during adolescence. Earlier studies have shown that this suppressed fear extinction during adolescence involves an altered glutamatergic plasticity in infralimbic medial prefrontal cortical (IL-mPFC) pyramidal neurons. However, it is unclear whether the excitability of IL-mPFC pyramidal neurons plays a role in this development-dependent suppression of fear extinction. Therefore, we examined whether fear conditioning and extinction affect the active and passive membrane properties of IL-mPFC layer 5 pyramidal neurons in pre-adolescent, adolescent and adult mice...
February 5, 2019: Synapse
A V Metts, H Rubin-Falcone, R T Ogden, X Lin, D E Wilner, A K Burke, M E Sublette, M A Oquendo, J M Miller, J J Mann
OBJECTIVE: We have previously reported higher brain serotonin 1A (5-HT1A ) autoreceptor binding in antidepressant-naïve patients with Major Depressive Disorder (MDD) compared with healthy volunteers, and a decrease in binding in MDD after selective serotonin reuptake inhibitor (SSRI) treatment. This SSRI effect is also present in rodents administered SSRI chronically. We therefore sought to determine the duration of antidepressant medication effects on 5-HT1A receptor binding after medication discontinuation...
January 28, 2019: Synapse
Batsheva Reich, Yan Zhou, Ellen Goldstein, Sudarshan S Srivats, Natalina H Contoreggi, Joshua F Kogan, Bruce S McEwen, Mary Jeanne Kreek, Teresa A Milner, Jason D Gray
In adult female, but not male, Sprague-Dawley rats, chronic immobilization stress (CIS) increases mossy fiber (MF) Leu-Enkephalin levels and redistributes delta- and mu-opioid receptors (DORs and MORs) in hippocampal CA3 pyramidal cells and GABAergic interneurons to promote excitation and learning processes following subsequent opioid exposure. Here, we demonstrate that CIS females, but not males, acquire conditioned place preference (CPP) to oxycodone and that CIS "primes" the hippocampal opioid system in females for oxycodone-associated learning...
January 10, 2019: Synapse
Thomas M Coate, M Katie Scott, Mansa C Gurjar
In mammals, hair cells and spiral ganglion neurons (SGNs) in the cochlea together are sophisticated "sensorineural" structures that transduce auditory information from the outside world into the brain. Hair cells and SGNs are joined by glutamatergic ribbon-type synapses composed of a molecular machinery rivaling in complexity the mechanoelectric transduction components found at the apical side of the hair cell. The cochlear hair cell ribbon synapse has received much attention lately because of recent and important findings related to its damage (sometimes termed "synaptopathy") as a result of noise overexposure...
December 28, 2018: Synapse
Tyler C Alexander, Frederico Kiffer, Thomas Groves, Julie Anderson, Jing Wang, Abdallah Hayar, Michelle T Chen, Analiz Rodriguez, Antiño R Allen
Cancer survivorship has increased greatly as therapies have become more advanced and effective. Thus, we must now focus on improving the quality of life of patients after treatment. After chemotherapy, many patients experience chemotherapy-induced cognitive decline, indicating a need to investigate pathologies associated with this condition. In this study, we addressed cognitive impairment after thioTEPA treatment by assessing behavior and assaying cytokine production and the structure of dendrites in the hippocampus...
December 26, 2018: Synapse
Sharon Thomson, Bailey Dyck, Ritesh Daya, Joella Ho, Ashley Bernardo, Yuxin Tian, Ram K Mishra
Schizophrenia is a mental disorder characterized by positive symptoms, negative symptoms, and cognitive dysfunction. Phencyclidine (PCP) - a N-methyl-D-aspartate (NMDA) receptor antagonist - induces symptoms indistinguishable from those of schizophrenia. A reduction of the phosphoprotein synapsin II has also been implicated in schizophrenia and has a well-known role in the maintenance of the presynaptic reserve pool and vesicle mobilization. This study assessed the behavioral and biochemical outcomes of chronic NMDA receptor antagonism in rodents and its implications for the pathophysiology of schizophrenia...
December 24, 2018: Synapse
Savannah Tollefson, Joshua Gertler, Michael L Himes, Jennifer Paris, Steve Kendro, Brian Lopresti, N Scott Mason, Rajesh Narendran
Phosphodiesterase-10a (PDE10a) is located exclusively in medium spiny neurons (MSN). Rodent studies show an increase in striatal MSN spine density following exposure to cocaine. These increases in MSN spine density are suggested to underlie neurobiological changes which contribute to cocaine self-administration. No postmortem or imaging studies have confirmed this finding in humans. Here, we hypothesized an increase in the MSN marker PDE10a in subjects with cocaine use disorder ("cocaine users") compared to controls...
January 2019: Synapse
Mahendra Singh, Brendan Lujan, Robert Renden
Synaptic vesicle (SV) exocytosis is intimately dependent on free local Ca2+ near active zones. Genetically encoded calcium indicators (GECIs) have become an indispensable tool to monitor calcium dynamics during physiological responses, and they are widely used as a proxy to monitor activity in neuronal ensembles and at synaptic terminals. However, GECIs' ability to bind Ca2+ at physiologically relevant concentration makes them strong candidates to affect calcium homeostasis and alter synaptic transmission by exogenously increasing Ca2+ buffering...
December 2018: Synapse
Alejandra Aketzalli Flores-Gómez, Ma de Jesús Gomez-Villalobos, Gonzalo Flores
Diabetes mellitus (DM) is characterized by high levels of blood glucose. In recent years, its prevalence has increased, which was 422 million in the world in 2014. In elderly patients, DM is associated with deficits in memory and learning processes. The cognitive deficits lead to dementia. With the development of animal models in DM, it has been possible to better understand quantitative morphological changes in numerous neuronal structures belonging to the limbic system, such as the prefrontal cortex (PFC), the hippocampus and basolateral amygdala (BLA)...
November 20, 2018: Synapse
Yuri Aono, Yuriko Watanabe, Manabu Ishikawa, Noboru Kuboyama, John L Waddington, Tadashi Saigusa
Cholinergic neurons in the nucleus accumbens contain GABAA and GABAB receptors that are thought to inhibit neural activity. We analyzed the roles of GABAA and GABAB receptors in regulating accumbal acetylcholine efflux of freely moving rats using in vivo microdialysis. The effects of GABA receptor ligands on the accumbal dopamine efflux were also analyzed because accumbal cholinergic and dopaminergic neurons could mutually interact. Drugs were applied intracerebrally through the dialysis probe. Doses of compounds indicate total amount administered (mol) during 30-60 min infusions...
November 18, 2018: Synapse
Alex L Deal, Maria A Mikhailova, Valentina P Grinevich, Jeff L Weiner, Raul R Gainetdinov, Evgeny A Budygin
The prefrontal cortex (PFC) plays a critical role in the control of many physiological processes including attention, learning and decision making (Dalley, Cardinal, & Robbins, 2004; Arnsten & Li, 2005; Funahashi & Andreau, 2013). This brain region receives dopamine (DA) and norepinephrine (NE) axons from the ventral tegmental area (VTA) and locus coeruleus (LC), respectively (Waterhouse, Lin, Burne, & Woodward, 1983; Chandler, Lamperski, & Waterhouse, 2013). Therefore, revealing alterations in catecholamine (CA) dynamics in these circuitries is necessary to understand the pathogenesis of different psychiatric diseases, including addiction to drugs and alcohol...
November 17, 2018: Synapse
Brisa García-Vilchis, Paola Suárez, Miguel Serrano-Reyes, Mario Arias-García, Dagoberto Tapia, Mariana Duhne, José Bargas, Elvira Galarraga
Different corticostriatal suprathreshold responses in direct and indirect striatal projection neurons (SPNs) of rodents have been reported. Responses consist in prolonged synaptic potentials of polysynaptic and intrinsic origin, in which voltage-gated Ca²⁺-currents play a role. Recording simultaneous Ca²⁺-imaging and voltage responses at the soma, while activating the corticostriatal pathway, we show that encoding of synaptic responses into trains of action potentials (APs) is different in SPNs: firing of APs in D1-SPNs increase gradually, in parallel with Ca²⁺-entry, as a function of stimulus intensity...
November 12, 2018: Synapse
Rodolfo Sánchez-Zavaleta, Hernán Cortés, José Arturo Avalos-Fuentes, Ubaldo García, José Segovia Vila, David Erlij, Benjamín Florán
Recent studies suggested the expression of CB2 receptors in neurons of the CNS, however, most of these studies have only explored one aspect of the receptors, i.e., expression of protein, messenger RNA, or functional response, and more complete studies appear to be needed to establish adequately their role in the neuronal function. Electron microscopy studies showed the presence of CB2r in asymmetric terminals of the substantia nigra pars reticulata (SNr), and its mRNA appeared is expressed in the subthalamic nucleus...
November 2018: Synapse
Anne E Homan, Stephen D Meriney
The impact of presynaptic transmitter release site organization on synaptic function has been a vibrant area of research for synaptic physiologists. Because there is a highly nonlinear relationship between presynaptic calcium influx and subsequent neurotransmitter release at synapses, the organization and density of calcium sources (voltage-gated calcium channels [VGCCs]) relative to calcium sensors located on synaptic vesicles is predicted to play a major role in shaping the dynamics of neurotransmitter release at a synapse...
November 2018: Synapse
Steven Vetel, Sophie Sérrière, Johnny Vercouillie, Jackie Vergote, Gabrielle Chicheri, Jean-Bernard Deloye, Frédéric Dollé, Sylvie Bodard, Claire Tronel, Lydie Nadal-Desbarats, Antoine Lefèvre, Patrick Emond, Sylvie Chalon
Parkinson's disease (PD) is characterized by the degeneration of dopaminergic (DA) neurons constituting the nigrostriatal pathway. Neuroinflammation, related to microglial activation, plays an important role in this process. Exploration of animal models of PD using neuroimaging modalities allows to better understand the pathophysiology of the disease. Here, we fully explored a moderate lesion model in the rat in which 6-hydroxydopamine was unilaterally delivered in three sites along the striatum. The degenerative process was assessed through in vivo Positron Emission Tomography (PET) imaging and in vitro autoradiographic quantitation of the striatal dopamine transporter (DAT) and immunostaining of tyrosine hydroxylase (TH)...
October 28, 2018: Synapse
Yi Chang, Hsi Lung Hsieh, Shu Kuei Huang, Su Jane Wang
Allopregnanolone, an active metabolite of progesterone, has been reported to exhibit neuroprotective activity in several preclinical models. Considering that the excitotoxicity caused by excessive glutamate is implicated in many brain disorders, the effect of allopregnanolone on glutamate release in rat cerebrocortical nerve terminals and possible underlying mechanism were investigated. We observed that allopregnanolone inhibited 4-aminopyridine (4-AP)-evoked glutamate release, and this inhibition was prevented by chelating the extracellular Ca2+ ions and the vesicular transporter inhibitor...
October 25, 2018: Synapse
Rajamani Selvam, Mason L Yeh, Eric S Levine
Brain-derived neurotrophic factor (BDNF), traditionally known for promoting neuronal growth and development, is also a modulator of synaptic transmission. In addition to the well-characterized effects at excitatory synapses, BDNF has been shown to acutely suppress inhibitory neurotransmission; however, the underlying mechanisms are unclear. We have previously shown that at inhibitory synapses in layer 2/3 of the somatosensory cortex, BDNF induces the mobilization of endogenous cannabinoids (eCBs) that act retrogradely to suppress GABA release...
October 17, 2018: Synapse
Zade R Holloway, Timothy G Freels, Josiah F Comstock, Hunter G Nolen, Helen J Sable, Deranda B Lester
Midbrain dopaminergic neurons project to and modulate multiple highly interconnected modules of the basal ganglia, limbic system, and frontal cortex. Dopamine regulates behaviors associated with action selection in the striatum, reward in the nucleus accumbens (NAc), emotional processing in the amygdala, and executive functioning in the medial prefrontal cortex (mPFC). The multifunctionality of dopamine likely occurs at the individual synapses, with varied levels of phasic dopamine release acting on different receptor populations...
October 13, 2018: Synapse
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