Cited by 713
The University of Texas Health Science Center at Houston
Publishes on Neuroscience and Neuropharmacology Research, Neurotransmitter Receptor Influence on Behavior, Receptor Mechanisms and Signaling. 264 papers and 12.7k citations.
Add your photo, update your bio, and get notified when your ranking changes.
Retinal dopamine-containing amacrine neurons are rapidly activated by light, as shown by an increase in the rate of dopamine formation in vivo and a concomitant increase in the activity of tyrosine hydroxylase, measured in vitro with a subsaturating concentration of pteridine cofactor. Activation of tyrosine hydroxylase also occurs when isolated eyes from rats killed in the dark are exposed to a strobe light. Studies of amacrine neurons should provide basic data about the biochemical processing of visual information, as well as the physiological presynaptic regulatory mechanisms of dopamine-containing neurons.
A simple, rapid method is presented for the determination of acetylcholine (ACh) and choline (Ch) in neuronal tissue using HPLC with electrochemical detection. The method is based on the separation of ACh and Ch by reverse-phase HPLC and mixing the effluent as it emerges from the column with acetylcholinesterase and Ch oxidase, which converts endogenous Ch and Ch produced by the hydrolysis of ACh to betaine and hydrogen peroxide. Production of hydrogen peroxide is continuously monitored electrochemically. The sensitivity of the procedure is 1 pmol for Ch and 2 pmol for ACh. Specificity of the method is based on HPLC, two specific enzymatic reactions, and the detection of hydrogen peroxide.
β-Phenylethylamine and serotonin were oxidatively deaminated by separate forms of monoamine oxidase of rat brain wimen studied in vitro . These forms, designated as type A and type B enzyme, have different characteristics. For example, type A enzyme deaminated serotonin, was sensitive to the drug clorgyline, was resistant to the drug deprenyl and was heat-stable. In contrast, type B enzyme deaminated β-phenylethylamine, was resistant to clorgyline, was sensitive to deprenyl and was heat-labile. Moreover, type A and type B enzyme activities could be partially separated by centrifugation on a continuous sucrose gradient. β-Phenylethylamine and serotonin are present in mammalian brain. We conclude from our studies that the amines of brain may be cataboblized by specific types of monoamine oxidase in vivo .