Browsing by Author "Niaz, Nasir"
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Item The acute cardiorespiratory effects of centrally injected arachidonic acid; the mediation of prostaglandin E, D and F-2 alpha(Elsevier, 2017-04-18) Erkan, Leman Gizem; Altınbaş, Burçin; Güvenç, Gökçen; Aydın, Begüm; Niaz, Nasir; Yalçın, Murat; Uludağ Üniversitesi/Veteriner Fakültesi/Fizyoloji Anabilim Dalı.; 0000-0002-5600-8162; AAR-6815-2021; AAC-4975-2022; AAG-6956-2021; 56529371200; 55356919300; 56529426800; 57194022849; 57060367600; 57192959734Arachidonic acid (AA), which is released from synaptic membrane phospholipid by neuroreceptor-initiated activation of phospholipase A(2), is abundant in the brain and works as a neurotransmitter and/or neuromodulator in the central nervous system. Recently we reported that centrally injected AA generated pressor and hyperventilation effects by activating thromboxane A(2) (TXA(2)) signaling pathway. The present study was designed to investigate the mediation of other metabolites of AA such as prostaglandin (PG) D, PGE and PGF(2 alpha), alongside TXA(2) in the AA-evoked cardiorespiratory effects in anaesthetized rats. Intracerebroventricular (i.c.v.) administration of AA caused pressor, bradycardic and hyperventilation responses by increasing pO(2) and decreasing pCO(2) in adult male anaesthetized Sprague Dawley rats. Pretreatment (i.c.v) with different doses of DP/EP prostanoid receptor antagonist, AH6809 or FP prostanoid receptor antagonist, PGF(2 alpha), dimethylamine partially blocked the cardiorespiratory and blood gas changes induced by AA. In conclusion, these data plainly report that central PGD, PGE or PGF(2 alpha) might mediate, at least partly, centrally administered AA-evoked cardiorespiratory and blood gas responses.Publication Contingent role of phoenixin and nesfatin-1 on secretions of the male reproductive hormones(Wiley, 2019-12) Güvenç, Gökçen; Altınbaş, Burçin; Kaşıkçı, Esra; Özyurt, Ebru; Baş, Ayşenur; Udum, Duygu; Niaz, Nasir; Yalçın, Murat; Uludağ Üniversitesi/Veteriner Fakültesi.; 0000-0002-1413-3651; 000-0002-9534-736X; 0000-0003-1591-510X; 0000-0001-7052-1694; 0000-0002-5600-8162; AAR-6815-2021; IYS-2646-2023; CZB-8484-2022; GDW-7164-2022; AAH-5167-2021; AAC-4975-2022; AAG-6956-2021; 56529426800; 55356919300; 57209073902; 57211540698; 57211534062; 31967936400; 7060367600; 57192959734Phoenixin (PNX) and nesfatin-1 are localised in the hypothalamus and the pituitary gland. Moreover, the most of the PNX-expressing neurons in the hypothalamus also co-express nesfatin-1. These outcomes may suggest that there is an interaction between PNX and nesfatin-1, at least in terms of neuroendocrine-mediated regulations. Hence, the study was planned to find out the effects of centrally delivered PNX and nesfatin-1 on male sex hormones or to show the interactive association of intracerebroventricularly (ICV) injected PNX+nesfatin-1 combination on the release of male hormones. PNX and nesfatin-1, single or together, were delivered ICV to different male Wistar Albino rat groups. Both PNX and nesfatin-1 induced a significant enhancement in plasma FSH, LH and testosterone without inducing any alteration in plasma GnRH in the rats. The central combinatorial treatment of both the neuropeptides produced a more potent rise in male plasma hormone levels than treating with single neuropeptide. In summary, our preliminary data show that centrally delivered PNX and nesfatin-1 can affect plasma male hormone levels. Moreover, that the combinatorial treatment with both the neuropeptides in male rats leading to a more potent effect on the plasma male hormone levels might suggest that both these neuropeptides act synergistically in terms of regulation of male HPGA.Item Histamine restores hemorrhage induced hypotension by activating cholinergic neurons in nucleus tractus solitarius(Elsevier, 2016-06-30) Altınbaş, Burçin; Güvenç, Gökçen; Erkan, Leman G.; İlhan, Tuncay; Niaz, Nasir; Yalçın, Murat; Uludağ Üniversitesi/Veteriner Fakültesi/Fizyoloji Anabilim Dalı.; Uludağ Üniversitesi/Veteriner Fakültesi/Histoloji ve Embriyoloji Anabilim Dalı.; 0000-0002-5600-8162; AAG-6956-2021; AAH-8859-2021; AAR-6815-2021; AAC-4975-2022; 55356919300; 56529426800; 56529371200; 16549312600; 57060367600; 57192959734The purpose of the current study is to investigate the functional connections between the central histaminergic and cholinergic systems at NTS level in hypotensive condition. Experiments were carried out in male Wistar Albino rats. The hypotension was achieved by withdrawing a total volume of 1.5 ml blood/100 g bodyweight over a period of 10 min. A microdialysis study was performed in NTS area to measure extracellular ACh and Ch levels. The hemorrhage produced a severe and long-lasting decrease in mean arterial blood pressure (MAP) and increase in extracellular ACh and Ch levels in NTS. Administration of histamine intracerebroventricularly (i.c.v.) or into the NTS reversed the hemorrhagic hypotension by increasing MAP and heart rate. I.c.v. injection of histamine also caused the additional increase in extracellular ACh and Ch levels. Moreover, central histamine injection augmented intracytoplasmic AChE immunoreactivity in NTS. These changes were completely blocked by histaminergic H1 receptor antagonist chlorpheniramine, but histaminergic H2 receptor blocker ranitidine and histaminergic H3/H4 receptor antagonist thioperamide failed to produce these effects. In conclusion, these findings are interpreted that brain histaminergic H1 receptor activation by central histamine injection may promote cholinergic stimulation in the NTS and subsequently reverses the hypotension.Item Intracerebroventricular injection of histamine induces the hypothalamic-pituitary-gonadal axis activation in male rats(Elsevier, 2018-11-15) Niaz, Nasir; Güvenç, Gökçen; Altınbaş, Burçin; Toker, Mehmed Berk; Aydın, Begüm; Udum, Duygu Küçükşen; Alçay, Selim; Gökçe, Elif; Üstüner, Burcu; Yalçın, Murat; Uludağ Üniversitesi/Veteriner Fakültesi/Fizyoloji Anabilim Dalı.; Uludağ Üniversitesi/Veteriner Fakültesi/Üreme ve Suni Tohumlama Anabilim Dalı.; Uludağ Üniversitesi/Veteriner Fakültesi/Biyokimya Anabilim Dalı.; 0000-0002-9534-736X; 0000-0002-7678-3289; 0000-0003-4033-9749; 0000-0002-5600-8162; AAR-6815-2021; IYS-2646-2023; ABA-6294-2020; A-2794-2014; AAC-4975-2022; AAG-6956-2021; AAG-7238-2021; 57060367600; 56529426800; 55356919300; 56780223500; 57194022849; 31967936400; 56099810300; 56779799700; 18937724600; 57192959734Brain 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.Item Merkezi histaminerjik sistemin hipotalamo-hipofizer-gonadal aksis üzerine etkilerinin araştırılması(Uludağ Üniversitesi, 2017) Niaz, Nasir; Yalçın, Murat; Uludağ Üniversitesi/Sağlık Bilimleri Enstitüsü/Fizyoloji Anabilim Dalı.Bu çalışmada, erkek sıçanlarda merkezi olarak enjekte edilen histaminin erkek hipotalamik-hipofizel-gonadal aksis üzerindeki etkileri ve bu etkilere merkezi sinir sisteminde bulunan histaminin H1R, H2R ve H3/4R'lerinin aracılığının araştırılması hedeflendi. Çalışmada 77 adet erkek Sprague Dawley ırkı sıçan kullanıldı. Sevofluran anestezisi altında plazma kan örneklerinin toplanabilmesi için sıçanların sol femoral arterlerine katater yerleştirildi. Merkezi yolla ilaç mikroenjeksiyonları için ise sıçanların serebral yan ventriküllerine kılavuz kanül yerleştirildi. Plazma GnRH, LH, FSH ve testosteron seviyelerini belirlemek için ise uygun ilaç enjeksiyonlarından önce ve enjeksiyondan sonraki 20., 40. ve 60. dakikalarda femoral artere yerleştirilen kateterden toplam 500 µl'lik kan örnekleri toplandı. Histaminin erkek hipotalamik-hipofizel-gonadal aksis üzerindeki etkilerini göstermek amacıyla histamin 50 ve 100 nmol dozlarında merkezi olarak uygulandı. Serebral yan ventriküle 50 nmol dozda histamin uygulanması, istatistiksel olarak anlamlı olmayan bir seviyede olmakla birlikte GnRH, LH, FSH ve testosteron hormonlarının seviyelerinde artışlar oluşturdu. Histaminin 100 nmol'lük dozunun merkezi olarak enjekte edilmesi ise, GnRH, LH, FSH ve testosteron hormonlarının seviyelerinde istatistiksel olarak anlamlı (p <0,05) artışların oluşmasına neden oldu. Merkezi olarak uygulanan H1R antagonisti klorfeniramin ve H2R antagonisti ranitidin ön tedavileri, histaminin üreme hormonları üzerindeki uyarıcı etkilerini tamamen bloke ederken, H3/4R antagonisti tioperamid ön tedavisi ise histaminin üreme hormonları üzerindeki uyarıcı etkilerinde herhangi bir değişiklik oluşturmadı. Sonuç olarak, çalışmamız ile elde edilen bulgular erkek sıçanlarda merkezi olarak uygulanan histaminin özellikle merkezi H1R ve H2R'lerini aktive ederek hipotalamustan GnRH salınımını, ardından hipofiz bezinden FSH ve LH salınımını ve en son olarak da testislerden testosteronun salınımını uyardığını ortaya koymaktadır.Item Modulation of nesfatin-1-induced cardiovascular effects by the central cholinergic system(Churchill Livingstone, 2018-05-03) Aydın, Begüm; Güvenç, Gökçen; Altınbaş, Burçin; Niaz, Nasir; Yalçın, Murat; Uludağ Üniversitesi/Veteriner Fakültesi/Fizyoloji Anabilim Dalı.; 0000-0002-5600-8162; 0000-0002-9534-736X; 0000-0002-1413-3651; AAR-6815-2021; AAC-4975-2022; AAG-6956-2021; HLA-3520-2023; IYS-2646-2023; 57194022849; 56529426800; 55356919300; 57060367600; 57192959734Nesfatin-1, a peptide whose receptor is yet to be identified, has been shown to be involved in the modulation of feeding, stress, and metabolic responses. Recently, increasing evidence has supported a modulatory role of nesfatin-1 in cardiovascular activity. We have previously reported that nesfatin-1 causes an increase in blood pressure in normotensive and hypotensive rats by increasing plasma catecholamine, vasopressin, and renin levels. Recent reports suggest that nesfatin-1 may activate the central cholinergic system. However, there is no evidence showing an interaction between central nesfatin-1 and the cholinergic system. Therefore, this study aimed to determine whether the central cholinergic system may have a functional role in the nesfatin-1-induced cardiovascular effect observed in normotensive rats. Intracerebroventricular injection of nesfatin-1 caused short-term increases in mean arterial pressure and heart rate responses including bradycardic/tachycardic phases in normotensive animals. Central injection of nesfatin-1 increased the acetylcholine and choline levels in the posterior hypothalamus, as shown in microdialysis studies. Central pretreatment with the cholinergic muscarinic receptor antagonist atropine and/or nicotinic receptor antagonist mecamylamine blocked nesfatin-1-induced cardiovascular effects. In conclusion, the results show that centrally administered nesfatin-1 produces a pressor effect on blood pressure and heart rate responses including bradycardic/tachycardic phases in normotensive rats. Moreover, according to our findings, the central cholinergic system can modulate nesfatin-1-evoked cardiovascular activity.Item Probing the mediation of central cyclooxygenase and lipoxygenase pathways in cardiovascular responses following central injection of orexin A(Wiley, 2016-09) Güvenç, Göken; İlhan, Leman Gizem; Altınbaş, Burçin; Aydın, Begüm; Niaz, Nasir; Yalçın, Murat; Uludağ Üniversitesi/Veteriner Fakültesi/Fizyoloji Anabilim Dalı.; 0000-0002-9534-736X; AAC-4975-2022; IYS-2646-2023; FCF-0163-2022; FBP-8021-2022; HLA-3520-2023; CHQ-8086-2022