Dihydroxyphenylalanine Production in Rat Brain Striatal Synaptosomes: Stimulation by a Calcium Chelator

Haycock, Dean A.; Patrick, Robert L.

doi:10.1111/j.1471-4159.1984.tb12690.x

Cited by 5 publications

(1 citation statement)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Drug effects on endogenous dopamine release were determined as previously described (Patrick and Barchas, 1976), utilizing aluminum oxide chromatography to purify the catecholamines and HPLC-electrochemical detection for catecholamine measurements (Haycock and Patrick, 1984). Each sample contained 30 ng dihydroxybenzylamine as an internal standard; recovery averaged 60%.…”

Section: Endogenous Dopamine Releasementioning

confidence: 99%

Diacylglycerol‐Induced Stimulation of Neurotransmitter Release from Rat Brain Striatal Synaptosomes

Davis

Patrick

1990

Journal of Neurochemistry

Self Cite

View full text Add to dashboard Cite

These studies were undertaken to test the hypothesis that alterations in phosphatidylinositol metabolism can modulate neurotransmitter release in the central nervous system. The effects of 1,2-diacylglycerols (DAGs) on dopamine release in the rat central nervous system were determined by measuring dopamine release from rat striatal synaptosomes in response to two DAGs (sn-1,2-dioctanoylglycerol and 1-oleoyl-2-acetylglycerol) that can activate protein kinase C and one DAG (deoxydioctanoylglycerol) that does not activate this kinase. Dioctanoylglycerol and 1-oleoyl-2-acetylglycerol, at a concentration of 50 micrograms/ml, stimulated the release of labeled dopamine from striatal synaptosomes by 35-50 and 17%, respectively. Dioctanoylglycerol-induced release was also demonstrated for endogenous dopamine. In contrast, deoxydioctanoylglycerol (50 micrograms/ml) did not stimulate dopamine release. Dioctanoylglycerol-induced dopamine release was independent of external calcium concentration, indicating a utilization of internal calcium stores. Dioctanoylglycerol (50 micrograms/ml) also produced a 38% increase in labeled serotonin release from striatal synaptosomes. The addition of dioctanoylglycerol to the striatal supernatant fraction increased protein kinase C activity. These results are consistent with the concept that an increase in phosphatidylinositol metabolism can stimulate neurotransmitter release in the central nervous system via an increase in DAG concentration. The data suggest an involvement of protein kinase C in the DAG-induced release, but other sites for DAG action are also possible.

show abstract

Section: Endogenous Dopamine Releasementioning

confidence: 99%

Diacylglycerol‐Induced Stimulation of Neurotransmitter Release from Rat Brain Striatal Synaptosomes

Davis

Patrick

1990

Journal of Neurochemistry

Self Cite

View full text Add to dashboard Cite

show abstract

The stability of 6-hydroxydopamine under minipump conditions

Haycock

Bear

1984

Exp Brain Res

View full text Add to dashboard Cite

A number of investigators have recently used osmotic minipumps to continuously deliver the neurotoxin 6-hydroxydopamine (6-OHDA) to kitten cerebral cortex for periods up to 7 days. Because this compound is known to be particularly labile, we studied the stability of 6-OHDA stored under conditions similar to those found in an osmotic minipump. In 0.4% ascorbic acid, 4 mM 6-OHDA-HBr was found to be stable for at least one week as determined by (1) assay of the drug by high performance liquid chromatography and electrochemical detection and (2) test of the drug's ability to deplete mouse heart norepinephrine.

show abstract

Activation of striatal tyrosine hydroxylase by in vivo electrical stimulation: Comparison with cyclic AMP-mediated activation

1990

View full text Add to dashboard Cite

These studies were carried out to characterize the activation of rat striatal tyroxine hydroxylase produced by depolarization of the medial forebrain bundle and to evaluate the possible role of cyclic AMP as a mediator of this activation. The enzymatic properties of tyrosine hydroxylase following in vivo depolarization were compared to those produced by treatment of striatal synaptosomes with dibutyryl cyclic AMP (dbcAMP). Similar effects were observed with regard to enzyme distribution, altered sensitivity to dopamine-induced inhibition, and activity as a function of tyrosine concentration. However, differences between the two treatments were also apparent. First, treatment with dbcAMP shifted the pH optimum from 6.2 to 7.0. In contrast, electrical stimulation decreased the rate of decline in activity as the pH was increased above the optimum, but did not shift the pH optimum. Second, plots of tyrosine hydroxylase activity versus cofactor concentration revealed two enzyme forms for both control and electrically stimulated preparations. However, dbcAMP treatment converted the enzyme to a single high affinity form. These results can be explained by one of the following: (1) cyclic AMP is the sole mediator of enzyme activation, but does not produce a maximally activated enzyme following in vivo depolarization, (2) cyclic AMP is only one of several mediators involved or (3) cyclic AMP is not involved in depolarization-induced activation, with activation occurring via the mediation of other intracellular messengers, such as calcium.

show abstract

Dihydroxyphenylalanine Production in Rat Brain Striatal Synaptosomes: Stimulation by a Calcium Chelator

Cited by 5 publications

References 20 publications

Diacylglycerol‐Induced Stimulation of Neurotransmitter Release from Rat Brain Striatal Synaptosomes

Diacylglycerol‐Induced Stimulation of Neurotransmitter Release from Rat Brain Striatal Synaptosomes

The stability of 6-hydroxydopamine under minipump conditions

Activation of striatal tyrosine hydroxylase by in vivo electrical stimulation: Comparison with cyclic AMP-mediated activation

Contact Info

Product

Resources

About