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Iyer V, Venkiteswaran K, Savaliya S, Lieu CA, Handly E, Gilmour TP, Kunselman AR, Subramanian T. The cross-hemispheric nigrostriatal pathway prevents the expression of levodopa-induced dyskinesias. Neurobiol Dis 2021; 159:105491. [PMID: 34461264 PMCID: PMC8597404 DOI: 10.1016/j.nbd.2021.105491] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 08/17/2021] [Accepted: 08/25/2021] [Indexed: 11/29/2022] Open
Abstract
Parkinson's disease (PD) is a neurodegenerative movement disorder that is routinely treated with levodopa. Unfortunately, long-term dopamine replacement therapy using levodopa leads to levodopa-induced dyskinesias (LID), a significant and disabling side-effect. Clinical findings indicate that LID typically only occurs following the progression of PD motor symptoms from the unilateral (Hoehn and Yahr (HY) Stage I) to the bilateral stage (HY Stage II). This suggests the presence of some compensatory interhemispheric mechanisms that delay the occurrence of LID. We therefore investigated the role of interhemispheric connections of the nigrostriatal pathway on LID expression in a rat model of PD. The striatum of one hemisphere of rats was first injected with a retrograde tracer to label the ipsi- and cross-hemispheric nigrostriatal pathways. Rats were then split into groups and unilaterally lesioned in the striatum or medial forebrain bundle of the tracer-injected hemisphere to induce varying levels of hemiparkinsonism. Finally, rats were treated with levodopa and tested for the expression of LID. Distinct subsets emerged from rats that underwent the same lesioning paradigm based on LID. Strikingly, non-dyskinetic rats had significant sparing of their cross-hemispheric nigrostriatal pathway projecting from the unlesioned hemisphere. In contrast, dyskinetic rats only had a small proportion of this cross-hemispheric nigrostriatal pathway survive lesioning. Crucially, both non-dyskinetic and dyskinetic rats had nearly identical levels of ipsi-hemispheric nigrostriatal pathway survival and parkinsonian motor deficits. Our data suggest that the survival of the cross-hemispheric nigrostriatal pathway plays a crucial role in preventing the expression of LID and represents a potentially novel target to halt the progression of this devastating side-effect of a common anti-PD therapeutic.
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Affiliation(s)
- Vishakh Iyer
- Department of Neurology and Neural and Behavioral Sciences, The Pennsylvania State University College of Medicine, Hershey, PA, United States of America
| | - Kala Venkiteswaran
- Department of Neurology and Neural and Behavioral Sciences, The Pennsylvania State University College of Medicine, Hershey, PA, United States of America
| | - Sandip Savaliya
- Department of Neurosurgery, The Pennsylvania State University College of Medicine, Hershey, PA, United States of America
| | - Christopher A Lieu
- Department of Neurology and Neural and Behavioral Sciences, The Pennsylvania State University College of Medicine, Hershey, PA, United States of America
| | - Erin Handly
- Department of Neurology and Neural and Behavioral Sciences, The Pennsylvania State University College of Medicine, Hershey, PA, United States of America
| | - Timothy P Gilmour
- Department of Electrical Engineering, John Brown University, Siloam Springs, AR, United States of America
| | - Allen R Kunselman
- Department of Public Health Sciences, The Pennsylvania State University College of Medicine, Hershey, PA, United States of America
| | - Thyagarajan Subramanian
- Department of Neurology and Neural and Behavioral Sciences, The Pennsylvania State University College of Medicine, Hershey, PA, United States of America.
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Venkiteswaran K, Alexander DN, Puhl MD, Rao A, Piquet AL, Nyland JE, Subramanian MP, Iyer P, Boisvert MM, Handly E, Subramanian T, Grigson PS. Transplantation of human retinal pigment epithelial cells in the nucleus accumbens of cocaine self-administering rats provides protection from seeking. Brain Res Bull 2015; 123:53-60. [PMID: 26562520 DOI: 10.1016/j.brainresbull.2015.11.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Revised: 10/30/2015] [Accepted: 11/05/2015] [Indexed: 01/05/2023]
Abstract
Chronic exposure to drugs and alcohol leads to damage to dopaminergic neurons and their projections in the 'reward pathway' that originate in the ventral tegmental area (VTA) and terminate in the nucleus accumbens (NAc). This damage is thought to contribute to the signature symptom of addiction: chronic relapse. In this study we show that bilateral transplants of human retinal pigment epithelial cells (RPECs), a cell mediated dopaminergic and trophic neuromodulator, into the medial shell of the NAc, rescue rats with a history of high rates of cocaine self-administration from drug-seeking when returned, after 2 weeks of abstinence, to the drug-associated chamber under extinction conditions (i.e., with no drug available). Excellent survival was noted for the transplant of RPECs in the shell and/or the core of the NAc bilaterally in all rats that showed behavioral recovery from cocaine seeking. Design based unbiased stereology of tyrosine hydroxylase (TH) positive cell bodies in the VTA showed better preservation (p<0.035) in transplanted animals compared to control animals. This experiment shows that the RPEC graft provides beneficial effects to prevent drug seeking in drug addiction via its effects directly on the NAc and its neural network with the VTA.
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Affiliation(s)
- Kala Venkiteswaran
- Department of Neurology, Penn State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA; Department of Neural and Behavioral Sciences, Penn State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA.
| | - Danielle N Alexander
- Department of Neural and Behavioral Sciences, Penn State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA.
| | - Matthew D Puhl
- Department of Neural and Behavioral Sciences, Penn State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA.
| | - Anand Rao
- Department of Neurology, Penn State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA.
| | - Amanda L Piquet
- Department of Neurology, Penn State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA.
| | - Jennifer E Nyland
- Department of Neural and Behavioral Sciences, Penn State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA.
| | - Megha P Subramanian
- Department of Neurology, Penn State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA; Department of Neural and Behavioral Sciences, Penn State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA.
| | - Puja Iyer
- Department of Neurology, Penn State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA.
| | - Matthew M Boisvert
- Department of Neural and Behavioral Sciences, Penn State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA.
| | - Erin Handly
- Department of Neurology, Penn State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA; Department of Neural and Behavioral Sciences, Penn State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA.
| | - Thyagarajan Subramanian
- Department of Neurology, Penn State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA; Department of Neural and Behavioral Sciences, Penn State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA.
| | - Patricia Sue Grigson
- Department of Neural and Behavioral Sciences, Penn State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA.
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