RESUMEN
The effects of haloperidol, reserpine, and concomitant lithium were evaluated in biochemical, endocrine, and behavioral studies in the rat. Concomitant administration of a chronic regimen of haloperidol and lithium did not prevent the development of tolerance as noted by dopamine metabolites in the striatum or olfactory tuberculum. Nor did chronic lithium alter behavioral response in rats treated with reserpine and challenged with the dopamine agonist apomorphine. Additionally, prolactin release was increased by haloperidol, but was not altered by acute or chronic lithium treatment. These findings are discussed in the light of present knowledge of pre- and postsynaptic receptor changes and the effects of lithium.
Asunto(s)
Conducta Animal/efectos de los fármacos , Dopamina/metabolismo , Haloperidol/farmacología , Litio/farmacología , Prolactina/metabolismo , Reserpina/farmacología , Ácido 3,4-Dihidroxifenilacético/metabolismo , Animales , Interacciones Farmacológicas , Ácido Homovanílico/metabolismo , Masculino , Ratas , Ratas EndogámicasRESUMEN
Chronic treatment of rats with choline caused a decrease in the hypothermic response to pilocarpine. The action of choline on the muscarinic receptors is consistent with electrophysiological and binding studies, supporting a direct muscarinic action for choline. Administration of direct muscarinic agonists has been shown to cause a decrease in the number of muscarinic receptors. Thus, the long-term use of cholinergic precursors could have some adverse effects on central cholinergic functioning.
Asunto(s)
Temperatura Corporal/efectos de los fármacos , Colina/farmacología , Pilocarpina/antagonistas & inhibidores , Animales , Masculino , Pilocarpina/farmacología , Ratas , Ratas EndogámicasRESUMEN
Choline was isolated from deproteinized plasma by cation-exchange chromatography. Isolated choline was directly converted to the 3,5-dinitrobenzoate derivative and was analyzed by paired-ion high-performance liquid chromatography with UV detection at 254 nm. An internal standard, 3-hydroxy-N,N,N-trimethylpropanaminium iodide was used for quantitation of plasma choline. Linearity was achieved from 1--500 nmole/ml with a reproducibility of +/- 6%. Plasma choline concentrations below 1 nmole/ml could not be accurately measured while plasma choline concentrations in the micromole/ml range deviated from linearity.