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Involvement of proopiomenalocortin-derived peptides in endogenous central histamine-induced reversal of critical haemorrhagic hypotension in rats

100%

Jochem J.

Journal of Physiology and Pharmacology

2004

tom 55

nr 1,1

An increase in endogenous central histamine concentrations, after loading with histamine precursor L-histidine or inhibition of histamine N-methyltransferase (HNMT) activity, produces the reversal of critical hypotension with improvement in survival of haemorrhage-shocked rats. In the present study, the involvement of proopiomelanocortin (POMC)-derived peptides in central histamine-induced resuscitating action was examined in male anaesthetised Wistar rats subjected to a haemorrhagic hypotension of 20-25 mmHg resulting in the death of all control animals within 30 min. HNMT inhibitor metoprine (20 µg) administered intracerebroventricularly (icv) at 5 min of critical hypotension produced a long-lasting pressor effect with a 100% survival rate at 2 h. The action was accompanied by 34.5% and 28.9% higher plasma concentrations of ACTH and alpha-MSH, respectively, in comparison to concentrations in the saline-injected group as measured 20 min after treatment. Melanocortin type 4 (MC4) receptor antagonist HS014 (5 µg; icv) inhibited metoprine-induced increase in mean arterial pressure, which resulted from decreased regional vascular resistance, however, it did not affect the heart rate and the survival at 2 h. On the other hand, glucocorticoid type II receptor blocker mifepristone (30 mg/kg; sc) had no effect. In conclusion, POMC-derived peptides, acting centrally via MC4 receptors, participate in endogenous central histamine-induced resuscitating effect in rats.

Concentrations of carnosine, anserine, L-histidine and 3-methyl histidine in boar spermatozoa and sheep milk by a modified HPLC method

80%

Ducci M. , Pacchini S. , Niccolini A. , Gazzano A. , Cerri D. , Gadea J. , Bobowiec R. , Sighieri C. , Martelli F.

Polish Journal of Veterinary Sciences

2006

tom 09

nr 3

The present study deals with the application ofhigh-perform ancc-liquid-chromatographyl(HPLC) method for a quantitative detection of carnosine, anserine, L-histidine and 3-methyl-L-histidine in biological material with o-phthaldialdehyde (OPA) post column derivatisation at the constant temperature of 50°C. For this purpose, some mobile-phases were prepared with scalar acetonitrile concentrations. A complete separation of all molecules, particularly for carnosine and 3-methyl-L-his- tidine, was obtained with a solution of acetonitrile and 6mM hydrochloric acid with 0.48 M sodium chloride (5%:95% v/v). Post column derivatisation reaction at temperature of 50°C permitted to obtain an increase in sensibility of all molecules. This method has been utilised for detection of histidine dipeptides in boar spermatozoa and in sheep milk. Concentrations (mean ± S.E. nmol/109 spermatozoa) of carnosine (0.96 ± 0.14) and anserine (0.83 ± 0.18) in boar spermatozoa were significantly lower than those of L-histidine (52.85 ± 4.86) and 3-methyl-L-histidine (83.07 ± 7.1). Positive correlation was found between carnosine and anserine contents (r=0.740; p<0.01) and between L-histidine and 3-methyl-L-histidine (r=0.657; p<0.01). All histidine dipeptides studied were also present in 40 samples of sheep milk. In a case of samples without unit-forming colonies (UFC) of Staphylococcus coagulase-positive, carnosine concentrations (9.17 ±0.89 nmol/ml) were higher than anserine (0.51 ±0.02 nmol/ml) and both were significantly lower in respect to L-histidine (49.51 ± 6.48 nmol/ml) and 3-metyl-L-histidine (81.21 ±6.82 nmol/ml). A negative correlation was observed between carnosine milk levels (r=-0.773; p<0.01) and UFC/ml of Staphylococcus coagulase-positive. In conclusion this very simple and fast method can be used to detect histidine dipeptides in biological compartments where their concentrations are very low.