Enhanced Expression of Heme Oxygenase-1 and Carbon Monoxide Excitatory Effects in Oxytocin and Vasopressin Neurones During Water Deprivation
| Autor: | Wagner Luis Reis, Sook Jin Son, Vinicia C. Biancardi, Javier E. Stern, José Antunes-Rodrigues |
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| Rok vydání: | 2012 |
| Předmět: |
medicine.medical_specialty
Vasopressin Endocrine and Autonomic Systems Endocrinology Diabetes and Metabolism Colocalization Membrane hyperpolarization Biology Supraoptic nucleus Heme oxygenase Cellular and Molecular Neuroscience chemistry.chemical_compound Endocrinology nervous system chemistry Oxytocin Hypothalamus Internal medicine medicine Neurotransmitter medicine.drug |
| Zdroj: | Journal of Neuroendocrinology. 24:653-663 |
| ISSN: | 0953-8194 |
| Popis: | A growing body of evidence supports carbon monoxide (CO) as a gas neurotransmitter within the central nervous system. While CO has been shown to affect neurohypophyseal hormone release in response to osmotic stimuli, the precise sources, targets and mechanisms underlying CO actions within the magnocellular neurosecretory system remain largely unknown. In this study, we combined immunohistochemistry and patch-clamp electrophysiology to study the cellular distribution of the CO-synthase enzyme heme oxygenase type 1 (HO-1), as well as CO actions on oxytocin (OT) and vasopressin (VP) magnocellular neurosecretory cells (MNCs) in euhydrated (EU) and 48h water-deprived rats (48WD). Our results show expression of HO-1 immunoreactivity both in OT and VP neurones, as well as in a small proportion of astrocytes, both in the supraoptic (SON) and paraventricular (PVN) nuclei. HO-1 expression, and its colocalization with OT and VP neurones within SON and PVN were significantly enhanced in 48WD rats. Inhibition of HO activity (CrMP 20μM) resulted in a slight membrane hyperpolarization in SON neurones from EU rats, without significantly affecting their firing activity. In 48WD rats, on the other hand, CrMP resulted in a more robust membrane hyperpolarization, significantly decreasing neuronal firing discharge. Taken together, our results indicate that magnocellular SON and PVN neurones express HO-1, and that CO acts as an excitatory gas neurotransmitter in this system. Moreover, we found the expression and actions of CO to be enhanced in water-deprived rats, suggesting that the state-dependent up-regulation of the HO-1/CO signalling pathway contributes to enhance MNCs firing activity during an osmotic challenge. |
| Databáze: | OpenAIRE |
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