GABA-A Receptor Antagonists

Publication Title: 
Neuropharmacology

The effect of the GABAA antagonists, bicuculline and picrotoxin, in the hot plate and writhing tests in mice and the paw-pressure test in rats was assessed. Subconvulsant doses of bicuculline (1.3-4 mumol kg-1, s.c.) or picrotoxin (0.8-2.5 mumol kg-1, s.c.) induced a dose-related increase in latency of licking in the hot plate test in mice, whereas subconvulsant doses of strychnine and thiosemicarbazide (0.9 and 6 mg kg-1, s.c. respectively), did not modify the threshold to thermal stimuli in mice.

Author(s): 
Malcangio, M.
Malmberg-Aiello, P.
Giotti, A.
Ghelardini, C.
Bartolini, A.
Publication Title: 
Masui. The Japanese Journal of Anesthesiology

The present investigation dealt with the effect of simultaneous administration of flumazenil on the hypnotic activity of propofol using a behavioral model of ddY mice. The mixed solution of propofol and flumazenil was administered intravenously into the mice tail vein and the achievement of hypnosis was defined as the loss of the righting reflex. Flumazenil 0.2 mg.kg-1 significantly decreased the required dose of propofol for hypnosis (8.43 +/- 0.46 mg.kg-1) compared to the control group (10.55 +/- 0.55 mg.kg-1).

Author(s): 
Adachi, Y.
Watanabe, K.
Uchihashi, Y.
Higuchi, H.
Satoh, T.
Publication Title: 
Anesthesiology

BACKGROUND: It is well documented that several general anesthetics, including propofol, potentiate glycine receptor function. Furthermore, glycine receptors exist throughout the central nervous system, including areas of the brain thought to be involved in sleep. However, the role of glycine receptors in anesthetic-induced hypnosis has not been determined. METHODS: Experiments were conducted in rats where the loss of righting reflex (LORR) was used as a marker of the hypnotic state.

Author(s): 
Nguyen, Hai T.
Li, Ke-yong
daGraca, Ralph L.
Delphin, Ellise
Xiong, Ming
Ye, Jiang H.
Publication Title: 
The American Journal of Chinese Medicine

The plant Withania somnifera (WS), also known as Ashwagandha, has been used widely in traditional medicine systems in India and Nepal (Ayurveda), and has been accepted to cure various ailments. In this study, the whole-cell patch clamp technique was performed to examine the mechanism of action of WS on the SG neurons of the Vc from mouse brainstem slices. In whole-cell patch clamp mode, methanol extract of Withania somnifera (mWS) induced short-lived and repeatable inward currents in all SG neurons tested (31.3 ± 8.51 pA, n = 7) using a high chloride pipette solution.

Author(s): 
Yin, Hua
Cho, Dong Hyu
Park, Soo Joung
Han, Seong Kyu
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: 
Anesthesiology

BACKGROUND: It is well documented that several general anesthetics, including propofol, potentiate glycine receptor function. Furthermore, glycine receptors exist throughout the central nervous system, including areas of the brain thought to be involved in sleep. However, the role of glycine receptors in anesthetic-induced hypnosis has not been determined. METHODS: Experiments were conducted in rats where the loss of righting reflex (LORR) was used as a marker of the hypnotic state.

Author(s): 
Nguyen, Hai T.
Li, Ke-yong
daGraca, Ralph L.
Delphin, Ellise
Xiong, Ming
Ye, Jiang H.
Publication Title: 
Journal of Ethnopharmacology

ETHNOPHARMACOLOGICAL RELEVANCE: Lavandula angustifolia (lavender) inhalation has been used in folk medicine for the treatment of anxiety, and clinical and animal studies have corroborated its anxiolytic effect, although its mechanism of action is still not fully understood. AIMS OF THE STUDY: The objective of the present study was to determine whether the GABAA/benzodiazepine complex or serotonin neurotransmission mediates the anxiolytic-like effect of lavender essential oil.

Author(s): 
Chioca, Lea R.
Ferro, Marcelo M.
Baretta, Irinéia P.
Oliveira, Sara M.
Silva, Cássia R.
Ferreira, Juliano
Losso, Estela M.
Andreatini, Roberto
Publication Title: 
American Journal of Physiology. Heart and Circulatory Physiology

Electroacupuncture (EA) causes prolonged suppression of reflex elevations in blood pressure for 1-2 h in anesthetized preparations. A long-loop pathway involving the arcuate nucleus (ARC), ventrolateral periaqueductal gray, and rostral ventrolateral medulla (rVLM) is involved in sympathoinhibitory cardiovascular EA effects. However, the mechanisms and locations of the prolonged EA inhibition are unknown. We hypothesized that this effect is mediated through a long-loop pathway involving opioid, nociceptin, and gamma-aminobutyric acid (GABA) receptor activation in the rVLM.

Author(s): 
Tjen-A-Looi, Stephanie C.
Li, Peng
Longhurst, John C.
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