Effects of ETB receptor stimulation and its subcellular pathways were evaluated in carbachol pre-contracted rabbit iris sphincter muscles (n=51). ETB stimulation with sarafotoxin (SRTX-c; 10-10-10-6 M) was tested in the absence (n=7) or presence of 10-5 M of: BQ-788 (ETB2 receptor antagonist; n=6), L-NA (NOS inhibitor; n=7) or indomethacin (cyclooxygenase inhibitor; n=10). Effects of ETB stimulation by endothelin-1 (ET-1; 10-10–10-7 M) in the presence of an ETA receptor antagonist (BQ-123; 10-5 M; n=7) and of ETB1 stimulation by IRL-1620 (10-10–10-7 M; n=7) were also tested. Finally, the effects of SRTX-c (10 -9 –10 -7 M) in electric field stimulation (EFS) contraction were evaluated (n=7). ETB receptor stimulation by SRTX-c or ET-1 in presence of BQ-123 promoted a concentration-dependent relaxation of the rabbit iris sphincter muscle by 10.8±2.0 % and 9.4±1.8 %, respectively. This effect was blocked by BQ-788 (-2.3±2.0 %), L-NA (4.5±2.3 %) or indomethacin (2.3±2.9 %). Selective ETB1 stimulation by IRL-1620 did not relax the iris sphincter muscle (0.9±5.4 %). EFS elicited contraction was not altered by SRTX-c. In conclusion, ETB receptor stimulation relaxes the carbachol precontracted iris sphincter muscle, an effect that is mediated by the ETB2 receptor subtype, through NO and the release of prostaglandins., A. Rocha-Sousa ... [et al.]., and Obsahuje seznam literatury
We measured hormonal levels in blood samples from pulmonary and radial arteries in 117 patients undergoing aorto-coronary by-pass surgery with the aim of investigating the role of the pulmonary vessel endothelium in hormone metabolism. Insulin and glucagon concentrations were significantly higher in pulmonary artery blood with respect to radial artery blood (73±65 vs. 65±47 pmol/l, p<0.005, and 80+49 vs. 73+51 ng/l, p<0.01, respectively), while no difference was found for growth hormone, prolactin, C peptide, insulin-like growth factor I, follicle stimulating hormone, luteinizing hormone, thyroid stimulating hormone, parathyroid hormone, thyroglobulin, triiodothyronine, thyroxine, free triiodothyronine, and free thyroxine. Moreover, prolactin concentrations were more than twice the normal levels, this being an effect of propafol and the opiate fentanyl used for the general anesthesia. Assuming that the arteriovenous differences observed are a marker of peptide hormone degradation, our study has demonstrated that with similar kinetics insulin and glucagon secreted into portal circulation and escaping from hepatic extraction undergo further homeostatic removal of about 9-10 % in the pulmonary circulation before entering the general circulation., G. Aliberti, I. Pulignano, M. Proietta, F. Miraldi, L. Cigognetti, L. Tritapepe, C. Di Giovanni, R. Arzilla, E. Vecci, M. Toscano., and Obsahuje bibliografii
FMRFamide-, vasoactive intestinal polypeptide (VIP)-, somatostatin-, substance P(SP)-, cholecystokinin octapeptide (CCK-8)- and pancreatic polypeptide (PP)-like materials were immunohistochemically detected in the endocrine cells and the gut innervation of diapausing pharate and newly-hatched first-instar larvae of Antheraea yamamai. SP- CCK-8-, PP- and FMRFamide-like immunoreactive cells were distributed unequally in different midgut regions; no cells reacting with antisera against VIP and somatostatin were found. Innervation of the anterior region of midgut, close to the foregut-midgut boundary, included 90-100 FMRFamide-like bipolar neurons that project along the midgut longitudinal muscles. No immunoreactive cell bodies were found in the foregut and hindgut, but nerve fibers with FMRFamide-like material were detected in hindgut muscles and extended over the posterior midgut. No changes in the distribution and intensity of immunostaining of both the endocrine cells and the gut innervation were found in four developmental stages between pre-diapause and hatching. SP-, CCK-8-, PP- and FMRFamide-like immunoreactive cells were also found in the CNS, indicating that the corresponding antigens belong to brain-gut regulatory peptides.