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The alpha2-adrenoceptors do not modify the activity of tyrosine hydroxylase, corticoliberine, and neuropeptide Y producing hypothalamic magnocellular neurons in the Long Evans and Brattleboro rats

100%

Bundzikova J., Pirnik Z., Zelena D., Mikkelsen J. D., Kiss A.

Journal of Physiology and Pharmacology

2010

tom 61

nr 4

391-398

The hypothalamic supraoptic (SON) and paraventricular (PVN) nuclei are activated by body salt-fluid variations. Stimulation of 2-adrenoceptors by an agonist-xylazine (XYL) activates oxytocinergic but not vasopressinergic magnocellular neurons. In this study, tyrosine hydroxylase (TH), corticoliberine (CRH), and neuropeptide Y (NPY) magnocellular phenotypes, were analysed in response to 2-adrenoceptor manipulations and sustained hyperosmolality in vasopressin deficient homozygous Brattleboro (di/di) rats. Saline (0.9% NaCl, 0.1 ml/100g/bw), XYL (10 mg/kg/bw), atipamezole (ATIP, 2-adrenoceptors antagonist, 1 mg/kg/bw), and ATIP 5 min later followed by XYL, were applied intraperitoneally. Presence of immunolabeled Fos peptide signalized the neuronal activity. Ninety minutes after injections, the rats were anesthesized and sacrificed by transcardial perfusion with fixative. Coronal sections of 30 µm thickness double immunolabeled with Fos/neuropeptide were evaluated under light microscope. Under basal conditions, di/di in comparison with control Long Evans rats, displayed significantly higher number of TH, CRH, and NPY immunoreactive neurons in the SON and PVN (except NPY cells in PVN) and more than 90%, 75%, and 86% of TH, NPY, and CRH neurons, respectively, displayed also Fos signal in the SON. XYL did not further increase the number of Fos in the PVN and SON and ATIP failed to reduce the stimulatory effect of hypertonic saline in all neuronal phenotypes studied. Our data indicate that hyperosmotic conditions significantly influence the activity of TH, CRH, and NPY magnocellular neuronal phenotypes, but 2-adrenoceptors do not play substantial role in their regulation during osmotic challenge induced by AVP deficiency.

Brain response to peripheral tumors in rats-the study of neurobiology of cancer

86%

Mravec B., Lackovicova L., Bundzikova J., Bizik J., Hulin L., Kiss A.

Acta Neurobiologiae Experimentalis

2009

tom 69

nr 3

A signifi cant amount of data has emerged supporting the hypothesis that the central nervous system might monitor and modulate tumor growth. The aim of our study was to investigate whether intraperitoneal tumor growth may induce detectable changes in brain structures that are involved in the response to immune challenges. Using Fos immunohistochemistry we investigated the effect of a tumor induced by a single intraperitoneal injection of BP6-TU2 fi brosarcoma cells to male Wistar rats on the activity of selected brain structures. Twenty eight days after the tumor cells administration we found an increased Fos expression in the nucleus tractus solitarii/A2, A1 noradrenergic cells, parabrachial nucleus as well as in the hypothalamic paraventricular, supraoptic and accessory neurons. These structures are involved in the processing of signals related to immune challenges and consequent elaboration of neuro-endocrine responses. Obtained data supports the view that the signals related to peripheral tumor development might be transmitted to the brain. Further studies are necessary to reveal whether our fi ndings can be attributed to a specifi c effect of cancer or whether observed changes in the activity of neuronal structures refl ex processes that only accompany the cancer progression.

Response of hypothalamic oxytocinergic neurons to immobilization stress is not dependent on the presence of corticotrophin releasing hormone (CRH): a CRH knock-out mouse study

86%

Pirnik Z., Petrak J., Bundzikova J., Mravec B., Kvetnansky R., Kiss A.

Journal of Physiology and Pharmacology

2009

tom 60

nr 2

77-82

This study explores the quantitative patterns of immunolabeled Fos protein incidence in the hypothalamic paraventricular (PVN) and supraoptic nuclei (SON) oxytocinergic (OXY) neurons in response to immobilization (IMO) stress in corticotrophin releasing hormone deficient (CRH-KO) mice. Adult male mice, taken directly from cages or 120 min after a single IMO, were sacrificed by intracardial perfusion with fixative. Coronal brain sections of 30 µm thickness were processed for dual Fos/OXY immunohistochemistry. In control wild type (WT) and CRH-KO mice, scattered Fos immunoreactivity was observed in hypothalamus, including the PVN where scanty Fos signal occurred in both parvocellular and magnocellular PVN subdivisions. Dual Fos/OXY immunostainings revealed higher basal Fos expression in the PVN of control CRH-KO mice. IMO evoked a marked rise in Fos expression in OXY neurons of the PVN and SON in both WT and CRH-KO groups of mice. The present data demonstrate that 1/ CRH deficiency upregulates the basal activity of hypothalamic PVN OXY cells in CRH-KO mice and 2/ IMO stress in both WT and CRH-KO mice affects distinctly the activity of OXY cells in both SON and PVN. Our data indicate that CRH deficiency does not alter the responsiveness of PVN and SON OXY cells to IMO stress.

Ograniczanie wyników

2 Journal of Physiology and Pharmacology

1 Acta Neurobiologiae Experimentalis

3 Bundzikova J.

3 Kiss A.

2 Mravec B.

2 Pirnik Z.

1 Bizik J.

1 Hulin L.

1 Kvetnansky R.

1 Lackovicova L.

1 Mikkelsen J. D.

1 Petrak J.

1 Zelena D.

1 2010

2 2009

Wyniki wyszukiwania

The alpha2-adrenoceptors do not modify the activity of tyrosine hydroxylase, corticoliberine, and neuropeptide Y producing hypothalamic magnocellular neurons in the Long Evans and Brattleboro rats

Brain response to peripheral tumors in rats-the study of neurobiology of cancer

Response of hypothalamic oxytocinergic neurons to immobilization stress is not dependent on the presence of corticotrophin releasing hormone (CRH): a CRH knock-out mouse study