Detail of "52809-07-1"

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Differential antagonism by chlorpromazine and diazepam of frog motoneurone depolarization induced by glutamate-related amino acids

Differential antagonism by chlorpromazine and diazepam of frog motoneurone depolarization induced by glutamate-related amino acids. Evans, Richard H.; Francis, Alison A.; Watkins, Jeffrey C. (Med. Sch., Univ. Bristol, Bristol, Engl.). Eur. J. Pharmacol., 44(4), 325-30 (English) 1977. CODEN: EJPHAZ. DOCUMENT TYPE: Journal CA Section: 1 (Pharmacodynamics) Section cross-reference(s): 2 The effects of some central depressant drugs on amino acid-induced depolarization of motoneurons have been detd. in the isolated hemisected frog spinal cord. Motoneuron deplarization was recorded from ventral roots and measurements were made in the presence or absence of procaine or tetrodotoxin to minimize indirect effects of both drugs and amino acid. Chlorpromazine [50-53-3] (0.05-0.1 mM) and diazepam [439-14-5] (0.5 mM) produced similar differential patterns of depression of amino acid-induced depolarizations. Responses induced by L-homocysteate [14857-77-3] were markedly antagonized by these drugs, while responses to quisqualate [52809-07-1] were unaffected. L-aspartate [56-84-8]-induced responses were antagonized more than L-glutamate [56-86-0]-induced responses. This pattern of antagonism resembles that previously described for Mg2+. In contrast, Na pentobarbital [57-33-0] (0.1 or 0.3 mM) and the inhibitory amino acids, GABA [56-12-2] and .beta.-alanine [107-95-9] (0.5-1.0 mM), depressed amino acid-induced responses in a more uniform manner. The differential effects obsd. with chlorpromazine and diazepam provide further support for the possibility that responses to excitant amino acids structurally related to L-glutamate may have different underlying mechanisms.

Possible interaction of [3H]glutamate binding sites with anion channels in rat neural tissues

Possible interaction of [3H]glutamate binding sites with anion channels in rat neural tissues. Yoneda, Yukio; Ogita, Kiyokazu; Nakamuta, Hiromichi; Koida, Masao; Ohgaki, Takao; Meguri, Haruo (Dep. Pharmacol., Setsunan Univ., Osaka 573-01, Japan). Neurochem. Int., 9(4), 521-31 (English) 1986. CODEN: NEUIDS. ISSN: 0197-0186. DOCUMENT TYPE: Journal CA Section: 2 (Mammalian Hormones) The effect of various ions on 3H-labeled L-glutamic acid (Glu) [56-86-0] binding was examd. using crude synaptic membrane prepns. from the rat brain. In vitro addn. of sodium acetate (1-100 mM) exhibited a significant enhancement of the binding in a concn.-dependent manner. Ammonium chloride (20 mM) prevented the potentiation by sodium acetate at 2°, whereas sodium acetate exerted an inhibitory action on the ammonium chloride-induced augmentation of the binding at 30°. Ammonium chloride (1-100 mM) itself elicited a temp.-dependent stimulation of the binding, which was invariably attenuated by an antagonist for the anion channels such as picrotoxin (10-3M) as well as by inhibitors of anion transport including ethacrynic acid (10-3 M) and 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (10-4-10-3 M), resp. The latter 2 inhibitors also caused a significant addnl. increase in the sodium acetate-induced enhancement of binding. A significant augmentation of binding resulted from the addn. (20 mM) of various anions known to penetrate the anion channels such as bromide, iodide, nitrate, bicarbonate, and thiocyanate in a permeability related manner, whereas that of nonpermeable anions including fluoride, sulfate, acetate, formate, phosphate, oxalate, lactate, succinate, and tartarate had no such effect on the binding. Addn. of D-aspartic acid [1783-96-6] resulted in the complete abolition of the Na+-dependent binding but spared the Cl--dependent binding. Scatchard anal. revealed that Cl- induced a 2-fold increase in the no. of the binding sites without affecting their affinity, whereas Na+ reduced the affinity with a concomitant increase of the no. of the binding sites. Addn. of quisqualic acid [52809-07-1] (10-5-10-3 M) inhibited the Cl--dependent binding of [3H]Glu to a significantly greater extent than the inhibition of Na+-dependent binding. N-Methyl-D-aspartic acid and kainic acid exerted no preventive action on the basal, Cl--dependent, and Na+-dependent binding, resp. Among various central structures examd., the highest basal binding activity was found in the retina. A significant basal binding activity of [3H]Glu was also detected in the pituitary and adrenal but not in the kidney. Cl exhibited a significant facilitation of [3H]Glu binding to central regions without altering that to peripheral tissues such as pituitary and adrenal. In contrast, Na+ induced significant attenuation of the binding to the pituitary, adrenal, and retina despite the occurrence of augmentation of the binding to other central structures. Thus, the Glu-binding sites may be linked to the anion channels in the rat central nervous system and this linkage may be absent from the pituitary, adrenal, and retina.