The fluorometric assay of catecholamines and related compounds: Improvements and extensions to the hydroxyindole technique

Laverty, R.; Taylor, Kenneth M.

doi:10.1016/0003-2697(68)90316-3

Cited by 704 publications

(81 citation statements)

References 5 publications

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“…The fluorometric determination of noradrenaline was carried out using 1 ml. of this eluate according to Laverty & Taylor (1968). The recovery for added internal standards of noradrenaline was: 86-7 + 1-9% (n = 5).…”

Section: Methodsmentioning

confidence: 99%

Negative feedback regulation of noradrenaline release by nerve stimulation in the perfused cat's spleen: differences in potency of phenoxybenzamine in blocking the pre‐ and post‐synaptic adrenergic receptors

Dubocovich¹,

Langer²

1974

The Journal of Physiology

193

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1. The effects of low concentrations of phenoxybenzamine (8·8 × 10−10 to 2·9 × 10−7 M) on responses and on noradrenaline overflow elicited by nerve stimulation were studied in the perfused cat's spleen. 2. In the presence of 8·8 × 10−10 M or 2·9 × 10−9 M phenoxybenzamine there was a significant reduction in responses to nerve stimulation while the overflow of the transmitter did not increase at the two frequencies of stimulation employed: 5 and 30 Hz. 3. In the presence of 2·9 × 10−8 M or 2·9 × 10−7 M phenoxybenzamine the responses to nerve stimulation were practically abolished and a significant increase in transmitter overflow was obtained at both frequencies of stimulation. The drug was more effective in increasing transmitter overflow at 5 Hz when compared with 30 Hz. 4. The higher effectiveness of phenoxybenzamine in blocking the post‐synaptic α‐receptor when compared with the blockade of the presynaptic α‐receptor that regulates transmitter release is compatible with the view that these two receptors are not identical. 5. A second alternative for the difference in effectiveness of phenoxybenzamine is that both types of α receptors are identical, but the spare receptor capacity for the presynaptic adrenergic receptors is higher than that of the post‐synaptic receptors.

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Section: Methodsmentioning

confidence: 99%

Negative feedback regulation of noradrenaline release by nerve stimulation in the perfused cat's spleen: differences in potency of phenoxybenzamine in blocking the pre‐ and post‐synaptic adrenergic receptors

Dubocovich¹,

Langer²

1974

The Journal of Physiology

193

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“…Endogenous catecholamines were determined by spectrophotofluorimetry (Laverty & Taylor, 1968). The ATP of the membranes (about 400,g proteins) was extracted three times with 0.5 ml HC104, adjusted to pH 6.0 with K2C03, injected into a Varian Aerograph LCS 1000 ion exchange liquid chromatograph (Varian, California, USA) (Brown, 1973) and measured by absorption at 254 nm.…”

Section: Assay Methodsmentioning

confidence: 99%

Discrimination of Monoamine Uptake by Membranes of Adrenal Chromaffin Granules

Prada

Obrist

Pletscher

1975

British J Pharmacology

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The accumulation of various radioactive monoamines by isolated membranes of bovine adrenal chromaffin granules was measured by equilibrium dialysis. Adenosine‐5′‐triphosphate (ATP) in the presence of Mg++ stimulated the uptake of all the amines tested, but the accumulation of dopamine, (‐)‐noradrenaline (NA), 5‐hydroxytryptamine (5‐HT), (±)‐adrenaline and (±)‐octopamine was greater than that of tyramine, (±)‐metaraminol, tryptamine, β‐phenylethy lamine and histamine. At the higher concentration levels of the amines in the medium the ATP‐dependent accumulation of dopamine, NA, adrenaline and 5‐HT in the membranes reached a saturation level, whereas in the absence of the nucleotide no saturation level was attained. Octopamine and 5‐HT competitively inhibited the ATP‐dependent uptake of NA. Decrease in the incubation temperature or the presence of N‐ethylmaleimide greatly reduced the ATP‐stimulated amine accumulation. Ouabain had no effect on uptake. Reserpine virtually abolished the ATP‐dependent uptake of dopamine, NA and 5‐HT, caused a partial inhibition of the metaraminol, octopamine and tyramine accumulation, but did not interfere with the uptake of tryptamine. The content of endogenous catecholamines of the membranes was changed very little by incubation of NA and 5‐HT in the presence of ATP. However, the membranes lost over 80% of their endogenous amines if incubated for 30 min without ATP. The ATP content of the medium progressively decreased during the incubation of granular membranes. It is concluded that the membrane of adrenal chromaffin granules discriminates between the various monoamines with regard to the magnitude of their uptake and that two mechanisms of ATP‐stimulated uptake, one responsive and the other resistant to reserpine, exist at the level of this membrane. The ATP‐stimulated transport at the granular membrane level may be an important factor in determining the intraneuronal storage of a physiological or false neurotransmitter.

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“…They were killed by a sharp blow on the head and the brain quickly removed. Following extraction , tissue levels of NA and dopamine were assayed by the trihydroxyindole fluorimetric procedure of Laverty & Taylor (1968).…”

Section: Methodsmentioning

confidence: 99%

The Effects of Acutely Administered Analgesics on the Turnover of Noradrenaline and Dopamine in Various Regions of the Rat Brain

Sugrue¹

1974

British J Pharmacology

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1 Noradrenaline and dopamine turnover rates were determined following blockade of synthesis by a-methyl-p-tyrosine. Morphine, pentazocine and methadone had no effect on steady state levels or on turnover of noradrenaline in whole brain and in the hypothalamus. Although morphine was without action on medulla-pons noradrenaline steady state levels, a drug-induced increase in turnover rate was observed which was antagonized by pretreatment with naloxone (5 mg/kg). Pentazocine and methadone failed to alter either the steady state level of noradrenaline in the medulla-pons or its turnover rate. 2 Morphine accelerated the decline in striatal a-methyl-m-tyramine levels following subcutaneous injection of a-methyl-m-tyrosine 18 h previously. 3 All three drugs increased the turnover of dopamine in whole brain and corpus striatum although the striatal effect was prevented by naloxone pretreatment. The minimum doses of morphine, pentazocine and methadone required to elicit a significant effect on striatal dopamine turnover were 10 mg/kg, 30 mg/kg and 10 mg/kg respectively. 4 The possibility of a dopaminergic involvement in the antinociceptive effect of analgesics is discussed.

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The fluorometric assay of catecholamines and related compounds: Improvements and extensions to the hydroxyindole technique

Cited by 704 publications

References 5 publications

Negative feedback regulation of noradrenaline release by nerve stimulation in the perfused cat's spleen: differences in potency of phenoxybenzamine in blocking the pre‐ and post‐synaptic adrenergic receptors

Negative feedback regulation of noradrenaline release by nerve stimulation in the perfused cat's spleen: differences in potency of phenoxybenzamine in blocking the pre‐ and post‐synaptic adrenergic receptors

Discrimination of Monoamine Uptake by Membranes of Adrenal Chromaffin Granules

The Effects of Acutely Administered Analgesics on the Turnover of Noradrenaline and Dopamine in Various Regions of the Rat Brain

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