Distribution of D1 and D5 dopamine receptors in the primate and rat basolateral amygdala

• Type of Material: Article
• Authors: E Christopher Muly, Emory University; Murat Senyuz, Emory University; Zafar U. Khan, University of Malaga; Jidong Guo, Emory University; Rimi Hazra, Emory University; Donald Rainnie, Emory University
• Language: English
• Date: 2009-09
• Publisher: Springer Verlag (Germany)
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © Springer-Verlag 2009
• Final Published Version (URL): http://link.springer.com/article/10.1007%2Fs00429-009-0214-8
• Title of Journal or Parent Work: Brain Structure and Function
• ISSN: 1863-2653
• Volume: 213
• Issue: 4-5
• Start Page: 375
• End Page: 393
• Grant/Funding Information: This work was supported by a Merit Award from the Office of Research and Development, Department of Veterans Affairs to ECM; MH069852 from the National Institutes of Health to DGR and BFU 2006-00306 from the Ministerio de Educacion y Ciencia to ZUK; and the Center for Behavioral Neuroscience (NSF agreement IBN-9876754), and by an NIH/NCRR base grant (P51RR000165) to Yerkes National Primate Research Center.
• Keywords: RT-PCR; ultrastructure; macaque; D5; non-human primate; dopamine; D1; receptor; electron microscopy; rodent; electrophysiology
• Research Categories: Psychology, Behavioral; Biology, Neuroscience

Abstract

Dopamine, acting at the D1 family receptors (D1R) is critical for the functioning of the amygdala, including fear conditioning and cue-induced reinstatement of drug self administration. However, little is known about the different contributions of the two D1R subtypes, D1 and D5. W identified D1-immunoreactive patches in the primate that appear similar to the intercalated cell masses reported in the rodent; however, both receptors were present across the subdivisions of the primate amygdala including the basolateral amygdala (BLA). Using immunoelectron microscopy, we established that both receptors have widespread distributions in BLA. The D1R subtypes colocalize in dendritic spines and terminals, with D1 predominant in spines and D5 in terminals. Single cell PCR confirmed that individual BLA projection neurons express both D1 and D5 mRNA. The responses of primate BLA neurons to dopamine and D1R drugs were studied using in vitro slices. We found that responses were similar to those previously reported in rat BLA neurons and included a mixture of postsynaptic and presynaptic actions. Given this we investigated the distribution of D1R in the rat BLA and found that there were similarities between the species, such as more prominent D5 localization to presynaptic structures. The higher affinity of D5 for dopamine suggests that presynaptic actions may predominate in the BLA at low levels of dopamine, while postsynaptic effects increase and dominate as dopaminergic drive increases. The results presented here suggest a complex action of dopamine on BLA circuitry that may evolve with different degrees of dopaminergic stimulation.