Inhibitory Postsynaptic Potentials

Publication Title: 
The Journal of Pharmacology and Experimental Therapeutics

Volatile anesthetics are used clinically to produce analgesia, amnesia, unconsciousness, blunted autonomic responsiveness, and immobility. Previous work has shown that the volatile anesthetic isoflurane, at concentrations that produce unconsciousness (250-500 microM), enhances fast synaptic inhibition in the brain mediated by GABA(A) receptors (GABA(A)-Rs). In addition, isoflurane causes sedation at concentrations lower than those required to produce unconsciousness or analgesia.

Author(s): 
Jia, Fan
Yue, Minerva
Chandra, Dev
Homanics, Gregg E.
Goldstein, Peter A.
Harrison, Neil L.
Publication Title: 
The Journal of Physiology

Gamma-aminobutyric acid A receptor (GABA(A)R)-mediated postsynaptic currents (IPSCs) were recorded from dopaminergic neurons of the ventral tegmental area of young rats in acute brain slices and from mechanically dissociated neurons. Low concentrations (0.1-0.3 microm) of muscimol, a selective GABA(A)R agonist, increased the amplitude, and reduced the paired pulse ratio of evoked IPSCs. Moreover, muscimol increased the frequency but not the amplitude of spontaneous IPSCs (sIPSCs). These data point to a presynaptic locus of muscimol action.

Author(s): 
Xiao, Cheng
Zhou, Chunyi
Li, Keyong
Ye, Jiang-Hong
Publication Title: 
Brain Research

Acidification, which occurs in some pathological conditions, such as ischemia and hypoxia often induces neurotoxicity. The activation of acid-sensing ion channels (ASICs), which are highly permeable to calcium, has been considered the main target responsible for calcium overload in ischemic/hypoxic brain. However, the influence of extracellular proton on GABAergic synaptic transmission is not well understood.

Author(s): 
Zhou, Chunyi
Xiao, Cheng
Deng, Chunyu
Hong Ye, Jiang
Publication Title: 
Brain Research

Labetalol, a combined alpha1, beta1, and beta2 adrenoceptor-blocking drug, has been shown to have analgesic properties in vivo. To determine the underlying mechanisms, we examined its effects on GABAA receptor-mediated spontaneous inhibitory postsynaptic currents (sIPSCs) and spontaneous firings of rat ventrolateral periaqueductal gray (PAG) neurons, either mechanically dissociated, or in acute brain slices. These PAG neurons mediate opioid-mediated analgesia and pain transmission and are under tonic control of GABAergic interneurons.

Author(s): 
Xiao, Cheng
Zhou, Chunyi
Atlas, Glen
Delphin, Ellise
Ye, Jiang Hong
Publication Title: 
The Journal of Pharmacology and Experimental Therapeutics

The current study investigated whether ethanol alters ATP activation of purinergic type 2 receptors (P2Rs) in the ventral tegmental area (VTA). The VTA is a key region of the brain that has been implicated in the development of alcohol addiction. We investigated the effects of ATP and ethanol on spontaneous inhibitory postsynaptic currents (sIPSCs) and the spontaneous firings in the VTA dopaminergic neurons, obtained using an enzyme-free procedure. These neurons preserved some functional GABA-releasing terminals after isolation.

Author(s): 
Xiao, Cheng
Zhou, Chunyi
Li, Kaixun
Davies, Daryl L.
Ye, Jiang H.
Publication Title: 
Neuropharmacology

The National Center for Complementary and Alternative Medicine (NCCAM) estimates that nearly 40% of adults in the United States use alternative medicines, often in the form of an herbal supplement. Extracts from the tree bark of magnolia species have been used for centuries in traditional Chinese and Japanese medicines to treat a variety of neurological diseases, including anxiety, depression, and seizures. The active ingredients in the extracts have been identified as the bi-phenolic isomers magnolol and honokiol.

Author(s): 
Alexeev, Mikhail
Grosenbaugh, Denise K.
Mott, David D.
Fisher, Janet L.
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