Background: γ-Aminobutyric acid (GABA) is the main inhibitory neurotransmitter in the brain where it regulates activity of neuronal networks. The receptor for glucagon-like peptide-1 (GLP-1) is expressed in the hippocampus, which is the center for memory and learning. In this study we examined effects of liraglutide, a GLP-1 analog, on GABA signaling in CA3 hippocampal pyramidal neurons.
Methods: We used patch-clamp electrophysiology to record synaptic and tonic GABA-activated currents in CA3 pyramidal neurons in rat hippocampal brain slices.
Results: We examined the effects of liraglutide on the neurons at concentrations ranging from one nM to one μM. Significant changes of the spontaneous inhibitory postsynaptic currents (sIPSCs) were only recorded with 100 nM liraglutide and then in just ≈50% of the neurons tested at this concentration. In neurons affected by liraglutide both the sIPSC frequency and the most probable amplitudes increased. When the action potential firing was inhibited by tetrodotoxin (TTX) the frequency and amplitude of IPSCs in TTX and in TTX plus 100 nM liraglutide were similar.
Conclusions: The results demonstrate that liraglutide regulation of GABA signaling of CA3 pyramidal neurons is predominantly presynaptic and more limited than has been observed for GLP-1 and exendin-4 in hippocampal neurons.
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http://dx.doi.org/10.1186/s40360-017-0191-0 | DOI Listing |
Brain Behav
January 2025
Department of Psychiatry, Dalhousie University, Halifax, Nova Scotia, Canada.
Introduction: Patients with bipolar disorder (BD) demonstrate episodic memory deficits, which may be hippocampal-dependent and may be attenuated in lithium responders. Induced pluripotent stem cell-derived CA3 pyramidal cell-like neurons show significant hyperexcitability in lithium-responsive BD patients, while lithium nonresponders show marked variance in hyperexcitability. We hypothesize that this variable excitability will impair episodic memory recall, as assessed by cued retrieval (pattern completion) within a computational model of the hippocampal CA3.
View Article and Find Full Text PDFSci Rep
January 2025
Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, 04510, Mexico City, Mexico.
Autism spectrum disorder (ASD) comprises alterations in brain anatomy and physiology that ultimately affect information processing and behavior. In most cases, autism is considered idiopathic, involving alterations in numerous genes whose functions are not extensively documented. We evaluated the C58/J mouse strain as an idiopathic model of ASD, emphasizing synaptic transmission as the basis of information processing.
View Article and Find Full Text PDFJ Neurosci
January 2025
Department of Neuroscience, The Ohio State University College of Medicine, Columbus, OH 43210
Pyramidal cells (PCs) in CA1 hippocampus can be classified by their radial position as deep or superficial and organize into subtype-specific circuits necessary for differential information processing. Specifically, superficial PCs receive fewer inhibitory synapses from parvalbumin (PV)-expressing interneurons than deep PCs, resulting in weaker feedforward inhibition of input from CA3 Schaffer collaterals. Using mice, we investigated mechanisms underlying CA1 PC differentiation and the development of this inhibitory circuit motif.
View Article and Find Full Text PDFSci Rep
January 2025
Department of Pathobiology, Faculty of Science, Mahidol University, Bangkok, Thailand.
Iron overload has been associated with cerebrovascular disease and cognitive impairment in β-thalassaemia patients, typically appearing earlier than in the general population. However, the mechanisms of iron overload on cerebrovascular pathology remain unclear. This study investigated the effects of heavy iron overload on the blood-brain barrier and neurohistology, particularly in the CA3 region of hippocampus and its contribution to cognitive impairment in β-thalassaemia mice.
View Article and Find Full Text PDFNeuropharmacology
March 2025
Department of Anesthesiology and Perioperative Medicine, Fuzong Clinical Medical College (900th Hospital of the Joint Logistic Support Force), Fujian Medical University, Fuzhou, Fujian, PR China.
The affective dimension in postsurgical pain is still poorly understood. Since neuropeptide oxytocin (OXT) has been implicated in a broad spectrum of pain and negative emotion, we investigated the potential therapeutic effect of intranasal OXT on postsurgical pain and associated anxiety in a mice model of plantar incision. The role of large conductance Ca(2+)-activated K(+) (BK(Ca)) channels was explored by using behavioral pharmacology experiments.
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