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  • Küçük Resim
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    Intracerebroventricular injection of histamine induces the hypothalamic-pituitary-gonadal axis activation in male rats
    (Elsevier Science Bv, 2018) Niaz, Nasir; Güvenç, Gökçen; Altınbaş, Burçin; Toker, Mehmed Berk; Aydın, Begüm; Udum Küçükşen, Duygu; Yalçın, Murat; Gökçe, Elif
    Brain histamine holds a key position in the regulation of behavioral states, biological rhythms, body weight, energy metabolism, thermoregulation, fluid balance, stress and reproduction in female animals. However, it is not clear whether central histamine exerts any effect on hypothalamic-pituitary-testicular in male rats and if so, the involvement of type of central histamine receptors. The current study was designed to determine the effect of centrally administrated histamine on plasma gonadotropin hormone-releasing hormone (GnRH), luteinizing hormone (LH), follicle stimulating hormone (FSH) and testosterone level, and sperm parameters, and to show the mediation of the central histaminergic H1, H2 and H3/H4 receptors on histamine-evoked hormonal and sperm parameters' effects. Studies were performed in male Sprague-Dawley rats. A total of 50 or 100 nmol doses of histamine were injected intracerebroventricularly (icy). 100 nmol dose of histamine significantly caused increases in plasma GnRH, LH, FSH and testosterone levels of animals, but not 50 nmol dose of histamine. Moreover, central pretreatment with chlorpheniramine, histaminergic H1 receptor antagonist (100 nmol), ranitidine and histaminergic H2 receptor antagonist (100 nmol) completely prevented histamine evoked increase in plasma GnRH, LH, FSH and testosterone levels, while thioperamide, histaminergic H3/H4 receptor antagonist (100 nmol) pretreatment failed to reverse sex hormones responses to histamine. Both central histamine treatment alone and central histamine treatment after central histaminergic receptors antagonists' pretreatments did not alter any sperm parameters in rats. In conclusion, our findings show that centrally administered histamine increases plasma GnRH, LH, FSH and testosterone levels of conscious male rats without change any sperm parameters. Moreover, according to our findings, central histaminergic H1, and H2 receptors mediate these histamine-induced effects.
  • Küçük Resim
    Öğe
    Long Term Incubation Resilience of Post-Thaw Ram Semen Diluted with Lecithin-Based Extender Supplemented with Bovine Serum Albumin
    (Kafkas Univ, Veteriner Fakultesi Dergisi, 2019) Alcay, Selim; Toker, Mehmed Berk; Gökçe, Elif; Önder, Nail Tekin; Üstüner, Burcu; Nur, Zekariya
    The objective of the study was to determine the optimum concentration of BSA in lecithin-based extender for post-thawing quality and incubation resilience (0 h, 6 h and 10 h) of ram sperm. Ejaculates were collected from five rams via electro ejaculation. Ejaculates were mixed to obtain pooled semen.Then, pooled semen was diluted with soybean lecithin-based extender without BSA (control) or supplemented with different concentrations of BSA (2.5 mg/mL, 5 mg/mL, 7.5 mg/mL and 10 mg/mL), at a final concentration of 150x106 spermatozoon/mL. Sperm motility, plasma membrane functional integrity (HOST), mitochondrial activity (rhodamine123), capacitation status (CTC), and DNA integrity (TUNEL) were evaluated. At the 10 h incubation, motility, plasma membrane functional integrity and mitochondria! function were better preserved in the BSA5 group compared to the control group. It was determined that high doses of BSA (5 mg/mL, 7.5 mg/mL and 10 mg/mL) affected acrosome reaction.The highest acrosome reaction rates were obtained in BSA10 groups in 6 h and 10 h incubation (P<0.05). TUNEL assay demonstrated that there were no differences among groups for DNA fragmentation at post-thaw and during incubation periods. The study shows that BSA supplemented extenders may have beneficial effect on ram semen parameters at 0 h, 6 h and 10 h of incubation. The results of the present study demonstrated a remarkable advantage of using 5 mg/mL of BSA in 1% lecithin-based extender.