Pyridazines

Publication Title: 
Neuropharmacology

We studied the effects of pentobarbital and antagonists of glutamate, gamma-aminobutyrate (GABA), and glycine receptors on extracellular activity in ventrobasal thalamic slices. Pentobarbital at sedative-hypnotic concentration (20 microM) reversibly induced 1-15 Hz oscillations. Sustained oscillations required electrical stimulation of internal capsule, but not elevated temperature or low [Mg2+]. Anesthetic concentration (200 microM) of pentobarbital evoked only transient oscillations. Kynurenate-sensitive glutamate receptors were essential for oscillations.

Author(s): 
Ran, I.
Mathers, D. A.
Puil, E.
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: 
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: 
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.
Publication Title: 
American Journal of Physiology. Regulatory, Integrative and Comparative Physiology

Stimulation of cardiopulmonary receptors with phenylbiguanide (PBG) elicits depressor cardiovascular reflex responses, including decreases in blood pressure and heart rate mediated in part by the brain stem parasympathetic cardiac neurons in the nucleus ambiguus (NAmb). The present study examined NAmb neurotransmitter mechanisms underlying the influence of electroacupuncture (EA) on the PBG-induced hypotension and bradycardia. We hypothesized that somatic stimulation during EA modulates PBG responses through opioid and γ-aminobutyric acid (GABA) modulation in the NAmb.

Author(s): 
Tjen-A-Looi, Stephanie C.
Li, Peng
Li, Min
Longhurst, John C.
Publication Title: 
American Journal of Physiology. Regulatory, Integrative and Comparative Physiology

Electroacupuncture (EA) at P5-P6 acupoints overlying the median nerves typically reduces sympathoexcitatory blood pressure (BP) reflex responses in eucapnic rats. Gastric distention in hypercapnic acidotic rats, by activating both vagal and sympathetic afferents, decreases heart rate (HR) and BP through actions in the rostral ventrolateral medulla (rVLM) and nucleus ambiguus (NAmb), leading to sympathetic withdrawal and parasympathetic activation, respectively. A GABAA mechanism in the rVLM mediates the decreased sympathetic outflow.

Author(s): 
Tjen-A-Looi, Stephanie C.
Guo, Zhi-Ling
Li, Min
Longhurst, John C.
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