Changes in serum proteins after endotoxin administration in healthy and choline-treated calves.

BACKGROUND: This study aimed to investigate the possible serum protein changes after endotoxin administration in healthy and choline-treated calves using proteomics. These results are expected to contribute to the understanding of the pathophysiological mechanisms of endotoxemia and the beneficial effect of choline administration in this clinical situation. METHODS: Healthy-calves (n = 20) were divided into 4 groups: Control, Choline treated (C), Lipopolysaccharide administered (LPS), and LPS + C. Control calves received 0.9 % NaCl injection. Calves in C and LPS + C groups received choline chloride (1 mg/kg/iv). Endotoxin (LPS) was injected (2 µg/kg/iv) to the calves in LPS and LPS + C groups. Serum samples were collected before and after the treatments. Differentially expressed proteins (> 1.5 fold-change relative to controls) were identified by LC-MS/MS. RESULTS: After LPS administration, 14 proteins increased, and 13 proteins decreased within 48 h as compared to controls. In the LPS group, there were significant increases in serum levels of ragulator complex protein (189-fold) and galectin-3-binding protein (10-fold), but transcription factor MafF and corticosteroid binding globulin were down regulated (≥ 5 fold). As compared with the LPS group, in LPS + C group, fibrinogen gamma-B-chain and antithrombin were up-regulated, while hemopexin and histone H4 were down-regulated. Choline treatment attenuated actin alpha cardiac muscle-1 overexpression after LPS. CONCLUSIONS: LPS administration produces changes in serum proteins associated with lipid metabolism, immune and inflammatory response, protein binding/transport, cell adhesion, venous thrombosis, cardiac contractility and blood coagulation. The administration of choline is associated with changes in proteins which can be related with its beneficial effect in this clinical situation.

Drugs with blocking effects on the renin-angiotensin-aldosterone system do not improve endothelial dysfunction long-term in hypertensive patients.

In essential hypertension, endothelial dysfunction has been documented many times and correlates with prognosis. The influence of the renin-angiotensin-aldosterone system (RAAS) on endothelial dysfunction has also been studied. The present study investigated the duration of the effects of RAAS-blocking drugs on endothelial function in 44 consecutive, never-treated, outpatients with mild to moderate hypertension. Patients (11 per group) received an angiotensin receptor blocker (ARB; irbesartan 300 mg/day or valsartan 160 mg/day) or an angiotensin-converting enzyme inhibitor (ACEi; fosinopril 10 mg/day or quinapril 20 mg/day). If target blood pressure (< 140/90 mmHg) was not achieved, 12.5 mg/day hydrochlorothiazide was added. Endothelial function, assessed by measuring brachial artery diameter, did not change significantly after 6 weeks, 1 year or 3 years of treatment in any group. Across all groups, endothelium-dependent and -independent vasodilation increased significantly after 6 weeks but, after 1 year, decreased below baseline and was at a similar level after 3 years; groups did not differ significantly. Both ACEi and ARB had similar effects on endothelial function; improvement occurred at the start of treatment but was not maintained. Endothelial dysfunction may be a resistant or irreversible feature of hypertension, requiring high doses of antihypertensive drugs and above-average patient compliance.

Morphine physical dependence intensification by hypoglycemia: NMDA receptor involvement.

The destruction of N-methyl-D-aspartate (NMDA) receptor-bearing neurons by insulin-induced hypoglycemia has long been known to be due to excessively released aspartate and glutamate. In this study, the effects of NMDA-bearing neuron destruction by insulin-induced hypoglycemia on the development of morphine (M) physical dependence, which was found related to functional states of NMDA receptors, were investigated. NMDA receptor antagonists CGP 39551 and MK-801 were used to see whether they could change intensity of precipitated abstinence syndrome by preventing destruction. Therefore, two groups of fasting rats injected IP with physiological saline, and another two groups given IP 10 mg/kg CGP 39551 and 0.5 mg/kg MK-801 received 15 IU/kg crystalline zinc insulin IP. After 2 h, the rats were orally given 2 x 4 ml of 5% glucose solution. On the third day, two pellets containing 75 mg base M were SC implanted to all rats. On the sixth day, they were IP given 2 mg/kg naloxone (NL). Then jumps, wet-dog shakes, and defecation were counted while diarrhea and ptosis were rated for 15 min. The rats given insulin manifested significantly more intense NL-precipitated abstinence syndrome than controls. The rats administered CGP 39551 showed a less intense physical dependence than those injected with only insulin. But, the intensity was still significantly higher than controls. In the rats that received MK-801, the abstinence syndrome was more or less equal to that in controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Vasopressin release by D-aspartic acid, morphine and prolyl-leucyl-glycinamide (PLG) in DI Brattleboro rats.

The L-asparaginase activities of the brains of the Wistar, heterozygous and homozygous Brattleboro rats divided into three parts namely the anterior, middle and posterior which respectively contained cerebral cortex, hippocampus + midbrain + thalamus + hypothalamus cerebellum + pons + medulla oblongata were estimated. The L-asparaginase activities of all the three parts in the homozygous Brattleboro rats were significantly higher than in the Wistar rats as well as in the heterozygous Brattleboro rats. Twenty min following the injections of 200 mg/kg D-aspartic acid, 20 mg/kg morphine, 200 mg/kg D-aspartic acid + 20 mg/kg morphine, 6 mg/kg prolyl-leucyl-glycinamide (PLG) and 6 mg/kg PLG + 20 mg/kg morphine the L-asparaginase activities of all three parts of the homozygous Brattleboro rat brains were found to be significantly inhibited. After having seen the suppressive effect of the drugs and their combinations used before the homozygous Brattleboro rats were given D-aspartic acid, morphine, D-aspartic acid + morphine, PLG and PLG + morphine for seven days. Then their plasma vasopressin levels were determined by RIA. The treatments applied to the homozygous Brattleboro rats caused the appearance of a significant amount vasopressin in the plasma. The results were interpreted as evidence for the fact that the inhibition of the brain L-asparaginase provides and/or accelerates the biosynthesis and/or release of vasopressin. As morphine has a vasopressin releasing and a brain L-asparaginase inhibiting effect the antidiuretic action of morphine was considered to be linked to its inhibitory effect on the brain L-asparaginase.

Brain asparaginase, ACE activity and plasma cortisol level in morphine dependent rats: effect of aspartic acid and naloxone.

The activities of the brain L-asparaginase and angiotensin converting enzyme (ACE), and the plasma cortisol level were found to be decreased in the rats implanted with morphine (M) containing pellets. Even though 10 mg/kg of naloxone (N) itself showed an inhibitory effect on ACE it abolished the inhibitions seen in the M dependent rats five min following subcutaneous injection. The chronic administration of L-aspartic acid (ASP) during the development of physical dependence or just before the N injection prevented the increase of the plasma cortisol caused by N. It is concluded that in addition to the inhibition of the brain L-asparaginase activity which was previously hypothesized to be the main reason of the development of physical dependence on opiates as a result of the related experimental and clinical data, the inhibition by M of the brain ACE activity may take part in the development of physical dependence. With regard to the plasma cortisol level, the concomitant administration of ASP with M blocks, to a great extent, the development of physical dependence on opiate. The single dose of ASP administration before N injection prevents the effect of N, the manifestation of abstinence syndrome.

The effect of morphine, naloxone, D- and L-aspartic acid on the brain and lung ACE in mice.

The brain and lung angiotensin converting enzyme (ACE) activities of the mice injected with 10 mg/kg morphine and/or naloxone, 200 mg/kg D- and/or L-aspartic acid were spectrophotometrically determined. Morphine, naloxone, D- and L-aspartic acid alone inhibited both brain and lung ACE activities whereas the combinations of morphine with naloxone, D-aspartic acid with L-aspartic acid and morphine with naloxone + L-aspartic acid showed no inhibitory effect on the brain ACE. While naloxone or L-aspartic acid partly antagonized the suppression of morphine on the lung ACE their combination completely prevented morphine from inhibiting the lung ACE. In the in vivo experiments performed on the brain and lung homogenates of the untreated mice the determination of the ACE activity in the incubating media containing 3.10(-3) M morphine or naloxone, 10(-2) M D- or L-aspartic acid showed a significant decrease in the activity. But no in vitro antagonistic effect was found by using the combinations of the drugs used in the study. The antagonism seen in the in vivo experiments was considered as an indirect one. And the relationship between the inhibitory effect of morphine, naloxone and D-aspartic acid, their suppressive effect on drinking and their beneficial effects in various forms of shock was discussed.

The in vitro and in vivo effects of enkephalins and beta-endorphin on ACE activity in mice.

The in vitro and in vivo effects of naloxone (NAL) and endogenous opioids namely methionine and leucine enkephalins (MET-ENK, LEU-ENK) and beta-endorphin (BETA-END) on the brain and lung angiotensin converting enzyme (ACE) activities were investigated. All three peptides dose -dependently inhibited ACE activity in vitro except 10(-5) M concentration of BETA-END which increased the lung ACE activity. NAL which intensified the in vitro inhibitory effect of the used opioids showed an antagonistic effect on the in vivo suppressive effect of BETA-END on both brain and lung ACE activities whereas it had neither antagonistic nor synergistic effect on the in vivo inhibiting effect of MET-ENK and LEU-ENK on the lung ACE activity. The results were consistent with those obtained by using morphine and NAL. As a result the possible contributory action of the excessively released endogenous opioids to overcome shock via their inhibiting effect on ACE was discussed.

Changes in brain and lung angiotensin converting enzyme activity in various shocks.

The brain and lung angiotensin converting enzyme (ACE) activities of the rats subjected to haemorrhagic, hypovolemic or endotoxic shock and of the mice immunized and then intravenously challenged with bovine serum albumin were determined by means of a spectrophotometric method. The lung ACE activities of all the shock groups were found significantly higher than those of their Control groups whereas only the brain ACE activities of the rats in endotoxic shock and the mice in anaphylactic shock showed a significant increase compared to their own control values. The results were interpreted as supporting evidence for the idea that peripheral and central renin-angiotensin systems may play a deleterious role in shock.