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Journal of Neural Transplantation and Plasticity
Volume 4, Issue 3, Pages 215-226
http://dx.doi.org/10.1155/NP.1993.215

Neurotransmitter Receptors in Fetal Tissue Transplants: Expression and Functional Significance

1Division of Neuroscience, Department of Psychiatry, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267-0559, USA
2Division of Neuroscience, Department of Anatomy, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267-0559, USA
3Division of Neuroscience, Department of physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267-0559, USA

Copyright © 1993 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Numerous studies have examined receptor expression in neural transplants and their possible role in transplant-induced functional recovery from lesion-induced deficits. Herein we attempt to summarize the results of these studies, especially those from studies involving striatal transplants. Autoradiographic studies indicate that dopamine D1 and D2, muscarinic, cholinergic, 5-HT2, opiate μ, β adrenergic and cholecystokinin (CCK) receptors are present in striatal transplants. Many of these receptors are present regardless of the transplant location and surrounding environment. This suggests that the expression of these receptors is determined by intrinsic properties of transplanted tissue, and is independent of transplant location and environment. Some transplant receptors, such as dopamine D1 and D2 and muscarinic receptors in striatal transplants, or 5-HT2 receptors in cortical transplants, display a patchy distribution which is dissimilar to that in the corresponding adult host tissue. This manuscript discusses this “abnormal” receptor distribution and possible explanations. Electrophysiological studies have indicated that some of the transplant receptors respond to physiological and pharmacological stimulation, suggesting that they are functional. However, the association of receptor expression with behavioral recovery is uncertain. The expression of neurotransmitter receptors in neural transplants may not be essential for the functional recovery associated with trophic mechanisms. However, neurotrammitter receptors may play an important role when functional recovery requires neur0anatomical integration between the host brain and the transplanted tissue.