Neuroscience research
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Neuroscience research · Sep 2018
Embryonic development of GABAergic terminals in the mouse hypothalamic nuclei involved in feeding behavior.
The inhibitory neurotransmitter gamma-amino butyric acid (GABA) plays important roles in energy balance and feeding behavior in the hypothalamus. To reveal the time course of GABAergic network formation, we examined the immunohistochemical localization of glutamic acid decarboxylase (GAD), a GABAergic neuron marker, vesicular GABA transporter (VGAT), a marker of inhibitory terminals, and K+-Cl--cotransporter2 (KCC2), which shifts GABA action from excitation to inhibition, in the developing mouse hypothalamus. GABAergic terminals, seen as GAD- and VGAT-positive dots, increased in density during embryonic development. ⋯ This suggested that after the formation of GABAergic terminals, GABAergic action may change to inhibition in the hypothalamus. This maturation appears to proceed as follows: the lateral hypothalamus (LH) matures first, followed by the paraventricular nucleus (PVN) by the time of birth, while the ventromedial hypothalamus (VMH) and the arcuate nucleus (Arc) are not fully mature at the time of birth. Our findings suggest that GABAergic networks in the "feeding center" (LH) and the "exit" (PVN) may mature before birth, while those in the "satiety center" (VMH) and "higher control center" (Arc) may mature after birth.
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Neuroscience research · Apr 2018
ReviewGamma oscillations in the entorhinal-hippocampal circuit underlying memory and dementia.
Gamma oscillations that occur within the entorhinal cortex-hippocampal circuitry play important roles in the formation and retrieval of memory in healthy brains. Recent studies report that gamma oscillations are impaired in the entorhinal-hippocampal circuit of Alzheimer's disease (AD) patients and AD animal models. ⋯ This review is especially salient for readers in Alzheimer's research field not familiar with in vivo electrophysiology. Recent studies have begun to show a causal link between gamma oscillations and AD pathology, suggesting that gamma oscillations may even offer a plausible future therapeutic target.
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Neuroscience research · Aug 2017
Pain-related evoked potentials after intraepidermal electrical stimulation to Aδ and C fibers in patients with neuropathic pain.
Neuropathic pain can result from neuronal hyperexcitability and complex interactions of the nociceptive pathways. Intraepidermal electrical stimulation (IES) is a novel technique that can selectively activate Aδ and C fibers. To investigate patterns of changes in Aδ- and C-mediated brain responses in patients with neuropathic pain using IES, we recorded pain-related evoked potential (PREP) after IES of Aδ and C fibers in 20 patients with neuropathic pain and 15 age-matched healthy volunteers. ⋯ PREP amplitude ratios after C/Aδ-fiber stimulation were significantly greater in the patient group than in the control group, and the higher ratio tended to be associated with a greater visual analog scale score. Patients with neuropathic pain had a tendency towards decreased Aδ amplitudes and significantly increased C/Aδ PREP amplitude ratios and this ratio appeared to be associated with the intensity of pain. Our findings suggest that decreased inhibition of the Aδ to C nociceptive systems is associated with generation of neuropathic pain.
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Neuroscience research · Jul 2016
Vasopressin and sympathetic system mediate the cardiovascular effects of the angiotensin II in the bed nucleus of the stria terminalis in rat.
The bed nucleus of the stria terminalis (BST) is involved in cardiovascular regulation. The angiotensin II (Ang II) receptor (AT1), and angiotensinogen were found in the BST. In our previous study we found that microinjection of Ang II into the BST produced a pressor response. ⋯ A selective vasopressin V1 receptor antagonist greatly attenuated the pressor effect of Ang II, indicating that the Ang II increases the arterial pressure via stimulation of vasopressin release as well. In conclusion, in the BST, Ang II as a neurotransmitter increases blood pressure by exciting cardiovascular sympathetic system and directly or indirectly causing vasopressin to release into bloodstream by VPN. This is an interesting new finding that not only circulating Ang II but also brain Ang II makes vasopressin release.
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Neuroscience research · Mar 2016
ReviewHereditary sensory and autonomic neuropathy types 4 and 5: Review and proposal of a new rehabilitation method.
Although pain is unpleasant, it should serve as a reminder for individuals to avoid similar damaging incidents in the future. Hereditary sensory and autonomic neuropathy (HSAN) includes genetic disorders involving various sensory and autonomic dysfunctions. They are classified by the mode of inheritance, clinical features, and related genes. ⋯ Studies on grasp-lift-holding tasks have shown higher grasp force and fluctuations in acceleration of the object. We believe that these findings represent outcomes of deficient motor learning. We propose a new rehabilitation method for patients with HSAN-4 and -5, with the aim of decreasing their destructive injuries.