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Louçano M, Coelho A, Chambel SS, Prudêncio C, Cruz CD, Tavares I. Noradrenergic Pathways Involved in Micturition in an Animal Model of Hydrocephalus-Implications for Urinary Dysfunction. Biomedicines 2024; 12:215. [PMID: 38255319 PMCID: PMC10813199 DOI: 10.3390/biomedicines12010215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 01/08/2024] [Accepted: 01/16/2024] [Indexed: 01/24/2024] Open
Abstract
Hydrocephalus is characterized by enlargement of the cerebral ventricles, accompanied by distortion of the periventricular tissue. Patients with hydrocephalus usually experience urinary impairments. Although the underlying etiology is not fully described, the effects of hydrocephalus in the neuronal network responsible for the control of urination, which involves periventricular areas, including the periaqueductal gray (PAG) and the noradrenergic locus coeruleus (LC). In this study, we aimed to investigate the mechanisms behind urinary dysfunction in rats with kaolin-induced hydrocephalus. For that purpose, we used a validated model of hydrocephalus-the rat injected with kaolin in the cisterna magna-also presents urinary impairments in order to investigate the putative involvement of noradrenergic control from the brain to the spinal cord Onuf's nucleus, a key area in the motor control of micturition. We first evaluated bladder contraction capacity using cystometry. Since our previous characterization of the LC in hydrocephalic animals showed increased levels of noradrenaline, we then evaluated the noradrenergic innervation of the spinal cord's Onuf's nucleus by measuring levels of dopamine β-hydroxylase (DBH). We also evaluated the expression of the c-Fos protooncogene, the most widely used marker of neuronal activation, in the ventrolateral PAG (vlPAG), an area that plays a major role in the control of urination by its indirect control of the LC via pontine micturition center. Hydrocephalic rats showed an increased frequency of bladder contractions and lower minimum pressure. These animals also presented increased DBH levels at the Onuf´s nucleus, along with decreased c-Fos expression in the vlPAG. The present findings suggest that impairments in urinary function during hydrocephalus may be due to alterations in descending noradrenergic modulation. We propose that the effects of hydrocephalus in the decrease of vlPAG neuronal activation lead to a decrease in the control over the LC. The increased availability of noradrenaline production at the LC probably causes an exaggerated micturition reflex due to the increased innervation of the Onuf´s nucleus, accounting for the urinary impairments detected in hydrocephalic animals. The results of the study provide new insights into the neuronal underlying mechanisms of urinary dysfunction in hydrocephalus. Further research is needed to fully evaluate the translational perspectives of the current findings.
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Affiliation(s)
- Marta Louçano
- Unit of Experimental Biology, Department of Biomedicine, Faculty of Medicine, University of Porto, 4200-319 Porto, Portugal; (M.L.)
- IBMC-Institute of Molecular and Cell Biology, University of Porto, 4200-135 Porto, Portugal
- I3S-Institute of Investigation and Innovation in Health, University of Porto, 4200-135 Porto, Portugal
- Chemical and Biomolecule Sciences, School of Health, Polytechnic of Porto, 4200-072 Porto, Portugal
| | - Ana Coelho
- Unit of Experimental Biology, Department of Biomedicine, Faculty of Medicine, University of Porto, 4200-319 Porto, Portugal; (M.L.)
- IBMC-Institute of Molecular and Cell Biology, University of Porto, 4200-135 Porto, Portugal
- I3S-Institute of Investigation and Innovation in Health, University of Porto, 4200-135 Porto, Portugal
| | - Sílvia Sousa Chambel
- Unit of Experimental Biology, Department of Biomedicine, Faculty of Medicine, University of Porto, 4200-319 Porto, Portugal; (M.L.)
- IBMC-Institute of Molecular and Cell Biology, University of Porto, 4200-135 Porto, Portugal
- I3S-Institute of Investigation and Innovation in Health, University of Porto, 4200-135 Porto, Portugal
| | - Cristina Prudêncio
- I3S-Institute of Investigation and Innovation in Health, University of Porto, 4200-135 Porto, Portugal
- Chemical and Biomolecule Sciences, School of Health, Polytechnic of Porto, 4200-072 Porto, Portugal
- Center for Translational Health and Medical Biotechnology Research (TBIO), Polytechnic of Porto, 4200-072 Porto, Portugal
| | - Célia Duarte Cruz
- Unit of Experimental Biology, Department of Biomedicine, Faculty of Medicine, University of Porto, 4200-319 Porto, Portugal; (M.L.)
- IBMC-Institute of Molecular and Cell Biology, University of Porto, 4200-135 Porto, Portugal
- I3S-Institute of Investigation and Innovation in Health, University of Porto, 4200-135 Porto, Portugal
| | - Isaura Tavares
- Unit of Experimental Biology, Department of Biomedicine, Faculty of Medicine, University of Porto, 4200-319 Porto, Portugal; (M.L.)
- IBMC-Institute of Molecular and Cell Biology, University of Porto, 4200-135 Porto, Portugal
- I3S-Institute of Investigation and Innovation in Health, University of Porto, 4200-135 Porto, Portugal
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