Hemodynamic characteristics of polypeptide substance P compared to bradykinin and prostaglandin E1

The effective doses of substance P, bradykinin and prostaglandin E1 that induced depressor responses in rats and rabbits were compared. On molar conversion substance P showed the most pronounced activity. There was an essential difference in doses that evoked standard responses in rabbits (the preparations were administered into the right or left heart ventricle). For bradykinin the dose difference was fivefold and prostaglandin E1 twenty-twofold. Substance P did not undergo inactivation in the lungs.     

Comparison of conformation characteristics of bradykinin and igercin molecules

A certain resemblance of three-dimensional molecular organizations of the known peptide bioregulator bradykinin (Arg-Pro-Pro-Gly-Phe-Ser-Pro-Phe-Arg) and the tentative cytophilic centre of the human IgE igercin (Arg-Ala-Val-Ser-Val-Asn-Pro-Gly-Lys) existing along with their pronounced structural similarity was shown by means of energy calculations. This is, however, not the case with the "biologically active" bradykinin conformations suggested earlier.     

Cardiovascular actions of python bradykinin and substance P in the anesthetized python, Python regius

The cardiovascular actions of python bradykinin (BK) and substance P (SP) have been investigated in the anesthetized ball python, Python regius. Bolus intra-arterial injections of python BK (0.03-3 nmol/kg) produced concentration-dependent increases in arterial blood pressure, heart rate (HR), and cardiac output concomitant with small decreases in systemic resistance and stroke volume. Intra-arterial injection of 3 nmol/kg python BK produced a tenfold increase in circulating concentration of norepinephrine, but epinephrine levels did not change. BK-induced tachycardia was attenuated (>90%) by the beta-adrenergic receptor antagonist sotalol, and the hypertensive response was attenuated (>70%) by the alpha-adrenergic receptor antagonist prazosin, indicating that effects of python BK are mediated at least in part by activation of the extensive network of adrenergic neurons present in vascular tissues. Bolus intra-arterial injections of python SP in the range 0. 01-30 pmol/kg produced concentration-dependent decreases in arterial blood pressure and systemic peripheral resistance concomitant with increases in cardiac output and stroke volume but with only minor effects on HR. The data suggest that kinins play a physiologically important role in cardiovascular regulation in the python.     

Raman studies on bradykinin and a cyclic bradykinin

Laser Raman spectra of bradykinin in water, deuterium oxide, and the solid phase were recorded. From the spectra it was concluded that bradykinin conformation is comprised of ordered and unordered structure. The ordered structure appears to be some form of reverse turn. Furthermore, it seems that there is an enhancement of the turn structure in the solid phase. A cyclic cystine containing analog of bradykinin was also examined with Raman spectroscopy. The cyclic bradykinin analog gives a Raman spectrum very similar to that of the linear bradykinin and therefore must share similar conformational forms with bradykinin. The restrictive Cys-Cys disulfide in the cyclic bradykinin must serve to maintain a conformation acceptable to bradykinin receptors since the cyclic peptide exhibits biological activity.     

Effect of bombesin, bradykinin, substance P and CGRP in prostate, bladder body and neck.

Lower urinary tract tissues respond heterogeneously to adrenergic and cholinergic agents. However, the action of bioactive peptides on these tissues has not been extensively studied. The contractile and relaxant effects of nine peptides-bradykinin, cholecystokinin, vasoactive intestinal polypeptide, gastrin, substance P, bombesin, neuropeptide Y, calcitonin gene-related peptide, and motilin-have been compared in the rat bladder body, bladder neck, and left ventral prostate in vitro. All three tissues contracted to bombesin and to bradykinin, although the bladder neck was less sensitive to the contractile effects of bradykinin than the other two tissues. Substance P only contracted the bladder body. Of all the peptides tested, relaxation was only observed to calcitonin gene-related peptide, which relaxed the bladder neck and prostate (phenylephrine-contracted) but not the bladder body (carbamylcholine-contracted). Thus lower urinary tract tissues are responsive to certain bioactive peptides in a nonhomogeneous fashion. These studies raise the possibility that selective modulation of peptide function may be an approach to therapy of urogenital disorders.     

Conformational analogy between substance P and physalaemin

The three-dimensional structure of physalaemin, pGlu-Ala-Asp-Pro-Asn-Lys-Phe-Tyr-Gly-Leu-Met-NH2, has been studied by one- and two-dimensional 500 MHz NMR spectroscopies in two solvents: methanol and dimethyl sulfoxide. As previously observed for substance P in methanol, the core of physalaemin 4----8 is folded into an helical conformation. This structure is stabilized by the presence of a salt bridge between Asp-3 and Lys-6 in both solvents. The only differences observed reside in the N-terminal sequences; the N-terminal tripeptide of substance is flexible whereas that of physalaemin is in an extended conformation.     

Activation of renal mechanosensitive neurons involves bradykinin, protein kinase C, PGE(2), and substance P

Increased renal pelvic pressure or bradykinin increases afferent renal nerve activity (ARNA) via PGE(2)-induced release of substance P. Protein kinase C (PKC) activation increases ARNA, and PKC inhibition blocks the ARNA response to bradykinin. We now examined whether bradykinin mediates the ARNA response to increased renal pelvic pressure by activating PKC. In anesthetized rats, the ARNA responses to increased renal pelvic pressure were blocked by renal pelvic perfusion with the bradykinin B(2)-receptor antagonist HOE 140 and the PKC inhibitor calphostin C by 76 +/- 8% (P < 0.02) and 81 +/- 5% (P < 0.01), respectively. Renal pelvic perfusion with 4beta-phorbol 12,13-dibutyrate (PDBu) to activate PKC increased ARNA 27 +/- 4% and renal pelvic release of PGE(2) from 500 +/- 59 to 1, 113 +/- 183 pg/min and substance P from 10 +/- 2 to 30 +/- 2 pg/min (all P < 0.01). Indomethacin abolished the increases in substance P release and ARNA. The PDBu-mediated increase in ARNA was also abolished by the substance P-receptor antagonist RP 67580. We conclude that bradykinin contributes to the activation of renal pelvic mechanosensitive neurons by activating PKC. PKC increases ARNA via a PGE(2)-induced release of substance P.     

Formation of human immunoreactive LMW and HMW-kininogens during coagulation. Comparison with bradykinin activity

Variations of the levels of human HMW and LMW kininogens have been studied in serum and in plasma incubated in vitro during 30 hours, at three different temperatures: 4 degrees, 22 degrees and 37 degrees C. There is a small difference between the level of LMW kininogen in plasma and in serum, but the serum and plasma level of LMW kininogen are almost stable during the time of incubation at the three temperatures. However, HMW kininogen is reduced in serum to about fifty percent of its plasma level. It decreases in plasma and in serum during incubation, overall at 4 degrees C. A strict parallelism stays between the radioimmunoassay and the bioassay.     

Treatment of sanitary-important bacteria by bacteriocin substance V24 in cattle dung water

Quantification of sanitary-important bacteria (e.g. Enterobacteriaceae), as well as indicators of environmental contamination, was assessed in samples of cattle dung from 25 cattle farms in 15 north-eastern Slovakia districts. The inhibitory effect of crude bacteriocin extract CBE V24 from Enterococcus faecalis V24 against Listeria monocytogenes Ohio and Yersinia enterocolitica YE85 was examined in cattle dung water with the aim of finding a new way of eliminating the health risk of the animal slurry. The following bacterial groups were quantified: Salmonella spp., Shigella-like spp. , Proteus spp., Enterobacter spp., Citrobacter spp., Pseudomonas spp. , Escherichia coli, Listeria spp., staphylococci, streptococci and enterococci (the average count ranged from 102 up to 104 cfu ml-1). Antagonistic effect of the crude bacteriocin from Enterococcus faecalis V24 in the range of 100-600 Arbitrary units per ml (AU ml-1) was shown against the following bacteria: Enterobacter cloacae, Ent. asburiae, Proteus spp., Salmonella spp., Acinetobacter lwoffi, L. monocytogenes as well as Y. enterocolitica YE85. During tests performed to study the inhibitory effect of the crude bacteriocin CBE V24 (concentration 800, 1600 AU ml-1) against L. monocytogenes Ohio and Y. enterocolitica YE85 in experimentally contaminated cattle dung, a reduction of 2.03 and 1.44 log cfu ml-1, respectively, was already noted after 1 h after crude bacteriocin CBE V24 addition.