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Query: UNIPROT:P01189 (
beta-endorphin
)
21,003
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Recent studies have revealed that the brain produces interferon-alpha (IFN-alpha) in response to noninflammatory as well as inflammatory stress and that it might have a role in normal physiology. When administered intracerebrally, IFN-alpha causes diverse effects including fever, anorexia, analgesia and changes in the central neuronal activities. These responses are inhibited by the opioid receptor antagonist naloxone. This is consistent with the reports suggesting that recombinant human (rh) IFN-alpha binds to opioid receptors in rodent brain membrane. We revealed that rhIFN-alpha altered the activity of thermosensitive neurons in the medial preoptic area (MPO) and glucose-responsive neurons in the ventromedial hypothalamus in an opioid-receptor-dependent way. As a stress which produces opioid-dependent analgesia is known to suppress the cytotoxicity of splenic natural killer cells, we investigated whether the administration of
beta-endorphin
and rhIFN-alpha may induce a similar immunosuppression. We found that central, but not peripheral, injection of both compounds inhibited natural killer (NK) cytotoxicity. Further studies revealed that rhIFN-alpha decreased the activity of MPO neurons via opioid receptors and the altered activity of MPO neurons in turn resulted in the activation of corticotropin-releasing factor neurons, thereby suppressing NK cytotoxicity predominantly through activation of the splenic sympathetic nerve and beta-receptor mechanisms in splenocytes. Thus, IFN-alpha may alter the brain activity to exert a feedback effect on the immune system. Further detailed whole-cell clamping analyses on neuronal mechanisms in rat brain tissue slices showed that the inhibitory effect of rhIFN-alpha on N-methyl-D-aspartate-induced membrane current responses of MPO neurons was mediated not only by opioid receptors but also by the local production of reactive oxygen intermediates,
nitric oxide
and prostanoids, possibly due to neuron-glial cell interaction.
...
PMID:Neuroimmunomodulatory actions of hypothalamic interferon-alpha. 973 Jun 83
It is clear that inflammatory processes contribute to neurodegenerative disease, stroke, closed head injury, encephalitis, and other CNS disorders. These inflammatory processes are marked by local increases in cytokines, in particular tumor necrosis factor-alpha (TNF-alpha). It is important to control such CNS inflammation in order to preserve neural function. The neuroimmunomodulatory peptide
alpha-melanocyte-stimulating hormone
(
alpha-MSH
) has been shown to modulate peripheral inflammation by acting on melanocortin receptors in host cells (macrophages, neutrophils) to inhibit production of such proinflammatory agents. Our results indicate that
alpha-MSH
likewise acts directly within the brain to modulate local inflammation. To determine if microglia are involved in anti-inflammatory responses to
alpha-MSH
within the brain, murine cells were tested; they produced TNF-alpha and
nitric oxide
in response to challenge, and production of both was reduced by
alpha-MSH
. In tests on human astrocytes, both
alpha-MSH
(1-13) and
alpha-MSH
(11-13) reduced TNF-alpha. Ischemia/reperfusion in the posterior circulation in dogs causes inflammatory reactions and disturbance of function, estimated from decreases in auditory-evoked potentials. These deficits were reduced by administering
alpha-MSH
systemically during reperfusion, moreso when the peptide was given during both ischemia and reperfusion. The results indicate that, much as for inflammation in the periphery,
alpha-MSH
modulates brain inflammatory responses mediated by proinflammatory agents.
...
PMID:Peptide modulation of inflammatory processes within the brain. 973 Jun 84
The present study was designed to investigate the role of
nitric oxide
(NO) in the regulation of adrenocortical function. Different NO donors, such as sodium nitroprusside (SNP), S-nitroso-L-acetyl penicillamine, diethylamine/NO complex sodium salt and diethylenetriamine NO adduct, significantly decreased corticosterone production both in unstimulated and in
corticotropin
-stimulated zone fasciculata adrenal cells, in a dose-dependent manner. The effect of SNP was reversed by ferrous hemoglobin. A selective inhibitor of NO synthase, L-NG-nitro-arginine significantly increased corticosterone secretion. The effect of SNP was not mediated by cGMP as permeable cGMP analogs did not reproduce its inhibitory effect. SNP significantly inhibited the steroidogenesis stimulated by 8Br-cAMP and 22(R)-OH-cholesterol, but was ineffective when corticosterone was produced in the presence of exogenously added pregnenolone. Moreover, the conversion of [3H]cholesterol to [3H]pregnenolone and the production of pregnenolone or progesterone (assessed by RIA) were significantly decreased by SNP. Taken together, these results suggest that NO may be a negative modulator of adrenal zona fasciculata steroidogenesis.
...
PMID:Effect of nitric oxide on rat adrenal zona fasciculata steroidogenesis. 977 63
We determined whether the gas carbon monoxide (CO) altered the
adrenocorticotropin
hormone (ACTH) response to mild inescapable electrofootshocks, and whether it interacted with
nitric oxide
(NO). Peripheral injection of the NO synthase (NOS) inhibitor Nwnitro-L-arginine-methylester (L-NAME), a compound which readily crosses the blood-brain barrier, produced the expected blunting of the ACTH response to the shocks. This effect was mimicked by other arginine analogues such as L-nitroarginine (L-NNA) and NG-methyl-L-arginine (NMMA). The subcutaneous (s.c.) administration of the heme oxygenase (HO) blockers tin mesoporphyrin (SnMP) or tin protoporphyrin (SnPP) significantly decreased brain HO levels, indicating that both compounds had penetrated the brain. Blood pressure showed a modest increase in response to SnMP, and no change after SnPP. SnMP and SnPP both decreased shock-induced ACTH release, though the magnitude of this effect was slightly less than that of L-NAME. The influence of SnPP was further augmented in rats with concomitant blockade of NO formation, which suggests that both NO and CO are necessary for the full response of this axis to electrofootshocks. Finally, the ability of SnPP to significantly blunt the expression of the mRNA for the immediate early gene NGFI-B in the paraventricular nucleus (PVN) of rats exposed to shocks, indicates that the influence of CO was exerted on hypothalamic neuronal activity. Collectively, our results show that NO and CO exert a stimulatory effect on the HPA axis response to mild electrofootshocks, and that at least part of this influence takes place on hypothalamic neurons and/or their afferents.
...
PMID:Influence of carbon monoxide, and its interaction with nitric oxide, on the adrenocorticotropin hormone response of the normal rat to a physico-emotional stress. 979 31
1. In humans, the hypertensive effects of
adrenocorticotropic hormone (ACTH)
infusion are reproduced by intravenous or oral cortisol. Oral cortisol increases blood pressure in a dose-dependent fashion. At a dose of 80-200 mg/day, the peak increases in systolic pressure are of the order of 15 mmHg. Increases in blood pressure are apparent within 24 h. 2. Cortisol-induced hypertension is accompanied by a significant sodium retention and volume expansion. Co-administration of the type I (mineralocorticoid) receptor antagonist spironolactone does not prevent the onset of cortisol-induced hypertension. Thus, sodium retention is not the primary mechanism of cortisol-induced hypertension. 3. Direct and indirect measures of sympathetic activity are unchanged or suppressed during cortisol administration, suggesting that cortisol-induced hypertension is not mediated by increased sympathetic tone. 4. Preliminary evidence in humans suggests that suppression of the
nitric oxide
system may play a role in cortisol-induced hypertension. 5. These potential mechanisms of cortisol action may be relevant in a number of clinical contexts, including Cushing's syndrome, apparent mineralocorticoid excess, the hypertension of liquorice abuse and chronic renal failure. There is also preliminary evidence suggesting a role for cortisol in essential hypertension.
...
PMID:Cortisol and hypertension. 980 93
The gas
nitric oxide
(NO) is an important messenger in brain signaling. Along with many other functions, NO is thought to influence the expression and/or release of various hypothalamic hormones (
corticotropin
-releasing hormone (CRH), gonadotropin-releasing hormone (GnRH) and vasopressin). To learn more about the role of NO in neuroendocrine mechanisms, we studied in mutant mice lacking neuronal isoform of NO synthase (nNOS) the cellular expression of CRH, neurophysin (the carrier protein of vasopressin/oxytocin) and
pro-opiomelanocortin (POMC)
, as well as of the POMC-derived peptides
beta-endorphin
(beta-END),
alpha-melanocyte-stimulating hormone
(
alpha-MSH
) and
corticotropin
(ACTH) by use of immunohistochemistry and in situ hybridization. Additionally, the remaining NO-generating capacities of the nNOS minus mice were investigated by NADPH-diaphorase histochemistry and citrulline immunohistochemistry as well as by immunohistochemical localization and Western blot analysis of endothelial NOS (eNOS) and nNOS isoforms. Amongst all hypothalamic peptides under investigation, only beta-END was found to be altered in mutant mice. A morphometric analysis of beta-END producing neurons of the arcuate nucleus revealed that significantly less cells were immunoreactive in mutant mice, whereas the expression of the precursor POMC as well as of other POMC-derived peptides was found to be unchanged. In addition to that, fewer beta-END-immunoreactive fibers were found in the paraventricular nucleus of nNOS minus mice in comparison to wild-type animals. Hence, the reduction of hypothalamic beta-END is probably a posttranslational event that might reflect a disturbed endorphinergic innervation of those hypothalamic neurons which normally express nNOS.
...
PMID:Expression of hypothalamic peptides in mice lacking neuronal nitric oxide synthase: reduced beta-END immunoreactivity in the arcuate nucleus. 987 4
The heptadecapeptide nociceptin, also known as Orphanin FQ, is a recently discovered endogenous ligand for the opioid-like G-protein coupled receptor, ORL1. In the present study, responses to nociceptin were investigated in isolated pressurized resistance arteries from the rat mesenteric vascular bed. Nociceptin in bath concentrations of 10(-9)-10(-6) M induced concentration-dependent increases in arterial diameter when the artery was precontracted with U46619; and administration of the structurally related opioid agonists, dynorphin A and
met-enkephalin
, had no effect on arterial diameter. Vasodilator responses to nociceptin were not altered by the opioid receptor antagonist naloxone or by the nitric oxide synthase inhibitor N(omega)-nitro-L-arginine. Responses to nociceptin were not altered by the muscarinic receptor blocking agent atropine or phentolamine, or the calcitonin gene-related peptide (CGRP) receptor antagonist CGRP-(8-37). These data suggest that nociceptin has direct vasodilator activity that is not dependent upon the activation of a traditional opioid receptor, muscarinic or CGRP receptors, an inhibitory effect on the adrenergic nervous system, or the release of
nitric oxide
in isolated resistance arteries from the rat mesentery.
...
PMID:Nociceptin, a novel endogenous ligand for the ORL1 receptor, dilates isolated resistance arteries from the rat. 987 48
Putative involvement of endogenous
nitric oxide
(NO) in the
corticotropin
-releasing hormone (CRH, 1 microg/kg i.p.)- and vasopressin (AVP, 5 microg/kg i.p.)-induced ACTH and corticosterone secretion was investigated in both non-stressed and crowded rats. The NO synthase blocker Nomega-nitro-l-arginine (l-NNA, 2 mg/kg i.p. ) significantly augmented the AVP-induced ACTH and corticosterone secretion in control and stressed rats, but it increased the CRH-induced ACTH response only in control rats. Crowding stress did not affect the l-NNA evoked increase in AVP-induced hormone responses, but it abolished the CRH-induced ACTH response.
...
PMID:Social stress inhibits the nitric oxide effect on the corticotropin-releasing hormone- but not vasopressin-induced pituitary-adrenocortical responsiveness. 988 72
Anaesthetized rats, endotracheally intubated and mechanically ventilated with room air, were subjected to a 5-min period of asphyxia by turning off the ventilator. The ventilator was then turned back on and, simultaneously, the animals were treated with either the
adrenocorticotropin
fragment 1-24 [ACTH-(1-24), 160 microg/kg in a volume of 1 ml/kg i.v.] or an equivalent volume of saline.
Nitric oxide
(NO)-haemoglobin formation was detected ex vivo in arterial blood by electron spin resonance spectrometry; arterial blood pressure, electrocardiogram (ECG) and electroencephalogram (EEG) were monitored for a 60-min observation period, or until prior death. During asphyxia, there was massive formation of NO (red cell concentrations 40-80 microM), associated with a dramatic fall in mean arterial pressure and pulse pressure, marked bradycardia and ECG signs of ischaemic damage, as well as an isoelectric EEG. Treatment with ACTH-(1-24) produced a prompt (within 15 min) and long-lasting drop in NO blood levels, associated with an almost immediate (within 1 min) restoration of cardiovascular function and with a more gradual recovery of EEG, which became normal after 3040 min; all parameters remained stable throughout the 60-min observation period. In saline-treated rats, on the other hand, there was a further increase in NO blood levels, as detected 3 min after treatment, and all died within 5-8 min. Moreover, pretreatment and treatment with S-methylisothiourea sulphate (SMT, 3 mg/kg i.v.), a relatively specific inhibitor of inducible NO synthase, inhibited NO formation, but did not affect the mortality rate (100% within 5-8 min). The present results provide the first evidence that prolonged asphyxia is associated with high blood concentrations of NO, and that the life-saving effect of melanocortin peptides in severe hypoxic conditions is associated with a complete normalization of NO blood levels. However, the lack of SMT protection in this experimental model seems to rule out the possibility that the ACTH-(1-24)-induced resuscitation is due to an effect on NO overproduction.
...
PMID:High blood levels of nitric oxide in rats subjected to prolonged respiratory arrest and their modulation during adrenocorticotropin-induced resuscitation. 993 51
beta-Endorphin blocks release of luteinizing hormone (LH)-releasing hormone (LHRH) into the hypophyseal portal vessels by stimulating mu-opiate receptors, thereby inhibiting secretion of LH. LHRH release is controlled by release of
nitric oxide
from nitricoxidergic (NOergic) neurons in the basal tuberal hypothalamus. To determine whether
beta-endorphin
exerts its inhibitory action on this NOergic pathway, medial basal hypothalami (MBH) from male rats were incubated with
beta-endorphin
(10(-8) M). beta-Endorphin decreased basal secretion of LHRH, and significantly inhibited the release of prostaglandin E2 (PGE2), a known stimulant of LHRH release. Incubation of MBH with
beta-endorphin
at various concentrations (10(-9)-10(-6) M) in vitro decreased the activity of NO synthase (NOS) (measured by the conversion of [14C]arginine to labeled citrulline). Conversely, the activity of NOS was increased by the mu-receptor antagonist, naltrexone (10(-8) M). Not only was the inhibitory action of
beta-endorphin
on LHRH and PGE2 release blocked by naltrexone (10(-8) M), but it increased NOS activity and LHRH and PGE2 release. beta-Endorphin also stimulated gamma-aminobutyric acid (GABA) release. Because GABA inhibits both nitroprusside (NP-induced PGE2 and LHRH release by blocking the activation of cyclooxygenase by NO, this is another mechanism by which
beta-endorphin
inhibits NP-induced PGE2 and LHRH release. The results indicate that
beta-endorphin
stimulates mu-opioid receptors on NOergic neurons to inhibit the activation and consequent synthesis of NOS in the MBH. beta-Endorphin also blocks the action of NO on PGE2 release and, consequently, on LHRH release, by stimulating GABAergic inhibitory input to LHRH terminals that blocks NO-induced activation of cyclooxygenase and consequent PGE2 secretion.
...
PMID:beta-Endorphin blocks luteinizing hormone-releasing hormone release by inhibiting the nitricoxidergic pathway controlling its release. 999 91
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