Brain and Pituitary-Adrenal Interactions Studies on Central Monoamine Neurons

Fuxé, Kjell; Hökfelt, T; Jönsson, G; Levine, Seymour; Lidbrink, Peter; Löfström, Anders

doi:10.1159/000394216

Cited by 23 publications

(9 citation statements)

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“…In this report, we confirm the sensitivity of CA central neurones to ADX [11,12,21,22,42,43,48]. However, the better anatomical resolution as well as the use of a sensitive index in order to characterize the activity of the CA neurones revealed clear-cut differential effects among the three major brain stem CA groups.…”

Section: Discussionsupporting

confidence: 72%

Differential Time Course Activation of the Brain Stem Catecholaminergic Groups following Chronic Adrenalectomy

1992

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The activity of the brain stem catecholaminergic (CA) cell groups of the ventrolateral (A₁C₁) and dorsomedial (A₂C₂) medulla that are known to contain primarily noradrenergic neurones (A₁ and A₂) and a smaller proportion of adrenergic cells (C₁ and C₂) as well as the noradrenergic group locus ceruleus (LC) in the dorsal pons was determined at various times up to 16 days following surgical adrenalectomy. The activity of the CA cell groups was estimated by the rate of tyrosine hydroxylation in vivo that was assessed by measuring the 3, 4-dihydroxyphenylalanine (DOPA) accumulated 20 min following administration of DOPA decarboxylase inhibitor NSD 1015. In the medullary nuclei noradrenaline content was found around 40- up to 70-fold the adrenaline content. This result was taken as evidence that the noradrenergic cells are likely to provide the main contribution to the tyrosine hydroxylation rate that we measured. Endogenous DOPA content represented between 2 and 10% of the noradrenaline content. NSD 1015 induced an accumulation of DOPA that was linear for at least 20 min and reached at this time more than 10-fold the endogenous level. While no modification of the in vivo tyrosine hydroxylation rate was observed in the LC, a significant increase was found in both medullary groups following adrenalectomy. In the A₁C₁ group it was detected 8 days after surgery and was then maintained with a maximum that represented up to a 60% increase over the basal value. In the A₂C₂ group the activation was slightly delayed and less marked. Increase in ACTH level occurred much earlier: it was about 70% of the maximal level already 4 days following adrenalectomy. The tyrosine hydroxylase activity measured in vitro with saturating concentrations of substrate and cofactors, was not affected by adrenalectomy. Daily injection of dexamethasone prevented the increase in plasma ACTH as well as the increase of the in vivo tyrosine hydroxylation rate in the medullary CA groups triggered by adrenalectomy. This activation is thus likely to be mediated by type II glucoreceptors and does not seem to involve an increase of the tyrosine hydroxylase content but rather other regulatory processes of the hydroxylation step in vivo. While the brain stem CA neurons are known to participate in the control of the hypothalamo-pituitary axis, their delayed activation following adrenalectomy suggests that they are not directly involved in the early increase in plasma ACTH level triggered by the lack of circulating corticosteroids.

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Section: Discussionsupporting

confidence: 72%

Differential Time Course Activation of the Brain Stem Catecholaminergic Groups following Chronic Adrenalectomy

1992

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“…The fact that the modification of plasma levels of P-EI induced by disruption of the VB was only temporary is in line with previous reports, including, for example, the tran sient enhancement of the ACTH response to stress seen in VB-lesioned rats, in demonstrating that an interference with catecholaminergic transmission does not result in perma nent deficits in adenohypophyseal secretion [7,46,48], Al though there may be a redundancy in control of [3-EI re lease, a supersensitivity to norepinephrine derived from un destroyed fibers may account for the recovery in P-EI secre tion. In fact, a 10-fold supersensitivity to the suppressive ef fect of norepinephrine upon CRF release was seen in rats treated 2 weeks previously with 6-hydroxydopamine [13].…”

Section: Discussionsupporting

confidence: 91%

“…As reviewed elsewhere, there is compelling evidence for the existence of a norepinephrinergic mechanism operating at a hypothal amic site which suppresses adenohypophyseal secretion of ACTH into plasma both tonicaliy and in response to stress [2, 7-9, 13, 36, 37, 46). Furthermore, we have recently ob served that, in contrast to lesions of the VB, selective des truction of the locus ceruleus, the primary source of the dor sal bundle, fails to modify plasma levels of P-EI [22], whilst the VB has similarly been identified as the norepinephriner gic system modulating ACTH release [7,8,9,36,46]. Our findings concerning P-EI are in good correspondence with those with ACTH in view of the coexistence and concomit ant outflow of adenohypophyseal P-EI and ACTH upon challenge by corticotrophic releasing factor (CRF) in vitro.…”

Section: Discussionmentioning

confidence: 99%

Lesions of the Ventral Noradrenergic (Norepinephrinergic) Bundle Affect Brain and Pituitary Pools of Endorphins and the Response of These to Stress in Rats

Millan¹,

Millan²,

Herz³

1982

Neuroendocrinology

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The present study examines the interrelationship of the ventral noradrenergic (norepinephrinergic) bundle (VB) with brain and hypophyseal pools of endorphins. As compared to sham-operated rats, selective destruction of the VB depressed hypothalamic levels of norepinephrine and abolished the fall in these levels evoked by acute foot shock stress. Stress elevated plasma levels of β-endorphin immunoreactivity (β-EI) and both basal and poststress circulating levels of β-EI were significantly greater in lesioned as compared to sham animals on days 4 and 10, but not 28, postsurgery. At each time, stress depleted the anterior and neurointermediate lobe content of β-EI in both sham-operated and lesioned rats. These data indicate that stress mobilizes β-EI from the pituitary into plasma and that the VB may inhibit the tonic and stress-elicited secretion of β-EI into the circulation. In lesioned rats, a transient depression in basal levels of β-EI in the septum and in those of met-enkephalin immunoreactivity (M-EI) in periventricular midbrain tissue was seen. Stress selectively depleted the β-EI as compared to the M-EI content of discrete brain regions, including the septum and this periventricular tissue, in sham-operated animals. Lesioned rats also responded to stress with a fall in β-EI levels and, in contrast to sham rats, with a decrease in the M-EI levels of the hypothalamus and periventricular tissue. These data demonstrate that the VB does not mediate the activation of brain β-EI elicited by stress and suggest the existence of an interaction of the VB with certain brain pools of β-EI and M-EI both tonically and under stress.

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“…Roth et al (1982) described increased adrenaline and noradrenaline concentration in the hypothalamus and hippocampus of rats after swim¬ ming in cold water dailv for 21 days. Because of the known inhibitory action of the ventral noradrenergic bundle in the rat, extensively innervating the hypothalamus, on the release of the corticotrophinreleasing hormone (Fuxe et al 1973;Weiner & Ganong 1978;Rose et al 1976; Moore & Bloom 1979;Gann et al 1978;Ganong 1980;Jones et al 1980) it is conceivaKe that suppression of ACTH release under conditions of prolonged stress may account for the decrease in plasma cortisol levels.…”

Section: Discussionmentioning

confidence: 99%

Changes in circadian rhythm and suppression of the plasma cortisol level after prolonged stress in the sheep

Przekop¹,

Stupnicka²,

Woliñska-Witort³

et al. 1985

Acta Endocrinologica

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Diurnal variations in the plasma cortisol level were studied in anoestrous, pro-oestrous and pregnant ewes subjected to weak electric stimulation of the forelimbs 9 h daily for 3 consecutive days. In non-pregnant ewes the cortisol level rose on each of the 3 days when the stimulation was applied and then decreased on the day following the stimulation. A similar decrease in plasma cortisol concentrations in pregnant ewes appeared on the second day of footshocking. The acrophase of the circadian rhythm on electrostimulation days was synchronous with the time of application of footshocks; therefore, in stimulated ewes it was significantly accelerated compared to the prestimulatory day. A decrease in the plasma cortisol level in pro-oestrous and pregnant ewes was accompanied by disappearance of its normal rhythmicity. Since a normal plasma cortisol response to exogenous corticotrophin was noted after 3 days of foot\x=req-\ shocking it seems unlikely that the decrease in the cortisol level after prolonged stress was caused by exhaustion of the adrenal cortex. Some central mechanisms which could account for the biphasic changes in the plasma cortisol level and for disturbances of the hormone diurnal rhythmicity under conditions of prolonged stress are discussed.Although considerable attention has been given to the effect of acute stress on the secretion of hvpophvsial and adrenal hormones, the influence of prolonged or chronic stress has been studied much less extensively, and contradictory results are re¬ ported in the literature. Dallman & Jones (1973) described, in immobilized male rats, a biphasic Requests for reprints to Dr. E. Domanski. variation of the plasma corticosterone level consist¬ ing of a rise during the first hour of restraint and a decrease after 4 h. On the other hand, Mikulaj et al. (1974) andTaché et al. (1976) showed that longterm stressing procedures increased adrenocortical activity in rats when applied for several days. In particular. Taché et al. (1976) found a progressive elevation of the plasma corticosterone level in male rats which were immobilized 8 h daily for 6 days.In previous studies we found that prolonged footshock disturbed oestrous cycles when admini¬ stered during 24 h to female rats (Chomicka et al., unpublished data) or during 9 h dailv up to 4 days in sheep (Przekop et al. 1984). The effect of stress on reproductive function was found to depend on the oestrous phase of its administration. These results prompted us to compare the effect of prolonged footshock on plasma cortisol levels, the classical index of responsiveness to stress, in anoestrous, pro-oestrous and pregnant ewes. Materials and Methods AnimahTwenty-six Polish Merino ewes 2.5-3.5 years old were used in this study. Thev were kept singly in 2 x 2 m compartments under natural light conditions, fed hay and concentrates and water ad libitum. In winter ambient temperature was maintained at 14 ± 2°C. Each animal bore an indwelling catheter in the jugular vein for drawing blood samples

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Brain and Pituitary-Adrenal Interactions Studies on Central Monoamine Neurons

Cited by 23 publications

References 0 publications

Differential Time Course Activation of the Brain Stem Catecholaminergic Groups following Chronic Adrenalectomy

Differential Time Course Activation of the Brain Stem Catecholaminergic Groups following Chronic Adrenalectomy

Lesions of the Ventral Noradrenergic (Norepinephrinergic) Bundle Affect Brain and Pituitary Pools of Endorphins and the Response of These to Stress in Rats

Changes in circadian rhythm and suppression of the plasma cortisol level after prolonged stress in the sheep

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