The concentration of dopamine and related monoamines in arteries and some other tissues of the sheep

Juorio, A. V.; Chedrese, P. Jorge

doi:10.1016/0742-8413(90)90079-o

Cited by 7 publications

(5 citation statements)

References 14 publications

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“…In the human, but not in every species, concentrations are above those in the adrenal glands, and in lungs of adult guinea-pigs they are greater than those of noradrenaline (Holzbauer & Sharman, 1972). In adult sheep, the lungs and caudate nucleus show the highest concentrations of many tissues studied; both have similar values, close to 10 ìg (g fresh tissue)¢ (Juorio & Chedrese, 1990). Although there are no values for lungs of fetal guinea-pigs, the sheep study allows us to make a reasonable estimate.…”

Section: Discussionsupporting

confidence: 52%

The effect of dopamine on lung liquid production by in vitro lungs from fetal guinea‐pigs

Chua

Perks

1998

The Journal of Physiology

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During gestation, fetal lungs produce large quantities of fluid which contribute substantially to the amniotic fluid, particularly in the guinea-pig, where production rates appear to be higher than those for urine (Strang, 1991;Perks et al. 1992). This production is based on a Na¤-K¤-2Cl¦ cotransport system, probably located in type II cells (Strang, 1991). However, at birth it is vital for this process to be replaced by fluid reabsorption, and it is generally agreed that this is brought about by an amiloride-sensitive, Na¤-based transport system, probably augmented by colloid osmotic effects (Strang, 1991). The first agent shown to activate fluid reabsorption was adrenaline (sheep: Walters & Olver, 1978; goat: Perks & Cassin, 1989). However, in the guinea-pig, reabsorption can be produced by both adrenaline and noradrenaline, which, unlike the â_receptor activation in sheep, act through Journal of Physiology (1998), 513.1, pp. 283-294 283The effect of dopamine on lung liquid production by in vitro lungs from fetal guinea-pigs 1. The neuroendocrine system of the lungs has no clear function. However, previous studies of one of its products, somatostatin, have implicated it in lung liquid removal at birth. The present study extends this concept by investigating the effects of dopamine, a major product of this system, on lung liquid reabsorption. 2. The effects of dopamine on fetal lung liquid production and reabsorption were tested on in vitro lungs from fetal guinea-pigs of 60 ± 2 days of gestation (term = 67 days). Dopamine was placed in the outer bathing saline during the middle hour of 3 h incubations. Fluid movements across the pulmonary epithelium were monitored by a dye dilution method, and changes in rates over 1 h intervals were tested for significance by analysis of variance and regression analysis. 3. Dopamine was able to reduce fluid production or cause reabsorption (based on 42 preparations). Control preparations and those given 10¦Ì Ò dopamine showed no significant changes; those given higher concentrations showed significant reductions in production or reabsorption (P < 0·025 to P < 0·0005), according to dose (42·6 ± 10·8 % reduction at 10¦Ê Ò; 75·4 ± 5·9 % reduction at 10¦É Ò; 92·1 ± 7·0 % reduction at 10¦Ç Ò and 121·4 ± 12·8 % (reabsorption) at 10¦AE Ò dopamine). The linear log dose-response curve (r = 0·99) showed a theoretical threshold at 1·7 ² 10¦Í Ò dopamine. 4. Effects were mediated through specific dopamine receptors (based on 78 preparations).Dopamine at 10¦É Ò was tested together with each of three dopamine receptor antagonists at 10¦Ç Ò. The general dopamine receptor antagonist haloperidol and the more specific Dµ receptor blocker domperidone both abolished responses, but the D1 receptor antagonist SCH23390 was without effect. This suggested that Dµ dopamine receptors mediated the responses, and that responses were not due to conversion of dopamine to adrenaline or noradrenaline. 5. There was no evidence that responses involved amiloride-sensitive Na¤ transport (based on 54 preparat...

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Section: Discussionsupporting

confidence: 52%

The effect of dopamine on lung liquid production by in vitro lungs from fetal guinea‐pigs

Chua

Perks

1998

The Journal of Physiology

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“…PE, a monoamine, has been found in low concentrations in the nervous tissue of all vertebrate and invertebrate species investigated so far (Durden et al, 1973;Juorio, 1976Juorio, , 1988Juorio and Philips, 1976;Juorio and Robertson, 1977;Philips et al, 1978;Reynolds et al, 1980;Juorio and Kazakoff, 1984;Juon o and Sloley, 1988;Juorio and Chedrese, 1990) (Tables 1 and 2). In the mammalian brain, although present in small quantities, PE has a heterogeneous distribution (Table 2), with the highest concentrations being associated with mesolimbic structures, where there are also high concentrations of the catecholamines.…”

Section: Presence and Distribution Of Pementioning

confidence: 92%

2‐Phenylethylamine: A Modulator of Catecholamine Transmission in the Mammalian Central Nervous System?

Paterson

Juorio

Boulton

1990

Journal of Neurochemistry

239

151

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Since the identification of 2‐phenylethylamine (β‐phenylethylamine; PE) as a biogenic amine, there has been much discussion about what role, if any, it may have in the CNS. Indeed, the low endogenous concentration of PE in the brain and its relatively low potency in behavioral and pharmacological experiments have led some researchers to conclude that perhaps PE possessed no physiological role at all but that it was merely a metabolic by‐product. Our findings have caused us to conclude otherwise, and in this article we review the neurochemical, neuropharmacological, and neurophysiological findings that lead us to propose that PE is a neuromodulator of catecholamine neurotransmission in the CNS.

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“…Lungs of ruminants contain high tissue DA concentrations (49,50), with a tissue DA:NE concentration ratio over 80. Catecholamine-fluorescent cells in intralobular tissue resemble mast cells and can be distinguished from neuronal fibers (51).…”

Section: Lungsmentioning

confidence: 99%

“…The mesenteric organs contribute substantially to total body production and metabolism of DA, both in laboratory animals and in humans (60 and unpublished observations). In sheep, duodenal DA concentrations average about 14 times those of NE (50). In rats, DA is formed from DOPA throughout the gastrointestinal tract, with the highest conversion rates in the small intestine and proximal colon (61).…”

Section: Gastrointestinal Systemmentioning

confidence: 99%

Is There a Third Peripheral Catecholaminergic System? Endogenous Dopamine as an Autocrine/ Paracrine Substance Derived from Plasma DOPA and Inactivated by Conjugation

et al. 1995

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In mammals, the sympathetic neurotransmitter is norepinephrine (NE), and the main adrenomedullary hormone is epinephrine (EPI). The sources and physiological roles of the third endogenous catecholamine, dopamine (DA), outside the brain have been obscure. Several lines of evidence suggest that in the periphery, rather than DA serving only as the precursor for the active compounds, released from sympathetic nerves and the adrenal medulla, DA may also act as an autocrine/paracrine regulator of local organ function. Thus, in the kidneys, most of DA formation appears to be from proximal tubular uptake of plasma DOPA, and binding of locally formed DA to dopaminergic receptors decreases Na/K ATPase activity and thereby accentuates natriuresis. In the gastric mucosa, DA may modulate sodium absorption and acid secretion. Recent clinical and laboratory animal evidence has indicated that the lungs and mesenteric organs contribute substantially to total body production and metabolism of DA. Generation of DA in non-noradrenergic, non-adrenergic cells can explain why human urine contains higher concentrations of DA and its metabolites than of NE and its metabolites. The vast preponderance of plasma DA in humans is sulfoconjugated. Since patients with sympathoneural failure have normal plasma levels of DA sulfate, one may speculate that the sulfoconjugating mechanism is relatively independent of sympathetic nerves and acts to localize DA effects and inactivate DA entering the circulation. These considerations lead to the concept of a third peripheral catecholaminergic system, where DA derived from plasma DOPA acts as an autocrine/paracrine substance and is inactivated by conjugation.

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The concentration of dopamine and related monoamines in arteries and some other tissues of the sheep

Cited by 7 publications

References 14 publications

The effect of dopamine on lung liquid production by in vitro lungs from fetal guinea‐pigs

The effect of dopamine on lung liquid production by in vitro lungs from fetal guinea‐pigs

2‐Phenylethylamine: A Modulator of Catecholamine Transmission in the Mammalian Central Nervous System?

Is There a Third Peripheral Catecholaminergic System? Endogenous Dopamine as an Autocrine/ Paracrine Substance Derived from Plasma DOPA and Inactivated by Conjugation

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