Subcellular localization of NAPE-PLD and DAGL-α in the ventromedial nucleus of the hypothalamus by a preembedding immunogold method
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The hypothalamus and the endocannabinoid system are important players in the regulation of energy homeostasis. In a previous study, we described the ultrastructural distribution of CB1 receptors in GABAergic and glutamatergic synaptic terminals of the dorsomedial region of the ventromedial nucleus of the hypothalamus (VMH). However, the specific localization of the enzymes responsible for the synthesis of the two main endocannabinoids in the hypothalamus is not known. The objective of this study was to investigate the precise subcellular distribution of N-arachidonoylphospatidylethanolamine phospholipase D (NAPE-PLD) and diacylglycerol lipase α (DAGL-α) in the dorsomedial VMH of wild-type mice by a high resolution immunogold electron microscopy technique. Knock-out mice for each enzyme were used to validate the specificity of the antibodies. NAPE-PLD was localized presynaptically and postsynaptically but showed a preferential distribution in dendrites. DAGL-α was mostly postsynaptic in dendrites and dendritic spines. These anatomical results contribute to a better understanding of the endocannabinoid modulation in the VMH nucleus. Furthermore, they support the idea that the dorsomedial VMH displays the necessary machinery for the endocannabinoid-mediated modulation of synaptic transmission of brain circuitries that regulate important hypothalamic functions such as feeding behaviors.
KeywordsEndocannabinoids Synthesizing enzymes Energy homeostasis Immunocytochemistry Electron microscopy
This work has been supported by The Basque Country Government Grant BCG IT764-13; Ministerio de Economía y Competitividad (MINECO) Grant BFU2012-33334; University of the Basque Country UPV/EHU UFI11/41 and Red de Transtornos Adictivos (RTA)—Instituto de Salud Carlos III grant RD12/0028/0004. L. Reguero was supported by a Postdoctoral Specialization Contract from the University of the Basque Country UPV/EHU.
- Colombo G, Agabio R, Diaz G, Lobina C, Reali R, Gessa GL (1998) Appetite suppression and weight loss after the cannabinoid antagonist SR 141716. Life Sci 63(8):PL113–PL117Google Scholar
- Cristino L, Starowicz K, De Petrocellis L, Morishita J, Ueda N, Guglielmotti V, Di Marzo V (2008) Immunohistochemical localization of anabolic and catabolic enzymes for anandamide and other putative endovanilloids in the hippocampus and cerebellar cortex of the mouse brain. Neuroscience 151:955–968PubMedCrossRefGoogle Scholar
- Egertová M, Cravatt BF, Elphick MR (2003) Comparative analysis of fatty acid amide hydrolase and cb(1) cannabinoid receptor expression in the mouse brain: evidence of a widespread role for fatty acid amide hydrolase in regulation of endocannabinoid signaling. Neuroscience 119:481–496PubMedCrossRefGoogle Scholar
- Mechoulam R, Ben-Shabat S, Hanus L, Ligumsky M, Kaminski NE, Schatz AR, Gopher A, Almog S, Martin BR, Compton DR, Pertwee RG, Griffin G, Bayewitch M, Barg J, Vogel Z (1995) Identification of an endogenous 2-monoglyceride, present in canine gut, that binds to cannabinoid receptors. Biochem Pharmacol 50:83–90PubMedCrossRefGoogle Scholar
- Reguero L, Puente N, Elezgarai I, Mendizabal-Zubiaga J, Canduela MJ, Buceta I, Ramos A, Suárez J, de Fonseca FR, Marsicano G, Grandes P (2011) GABAergic and cortical and subcortical glutamatergic axon terminals contain CB1 cannabinoid receptors in the ventromedial nucleus of the hypothalamus. PLoS ONE 6:e26167PubMedCentralPubMedCrossRefGoogle Scholar
- Tanimura A, Yamazaki M, Hashimotodani Y, Uchigashima M, Kawata S, Abe M, Kita Y, Hashimoto K, Shimizu T, Watanabe M, Sakimura K, Kano M (2010) The endocannabinoid 2-arachidonoylglycerol produced by diacylglycerol lipase alpha mediates retrograde suppression of synaptic transmission. Neuron 65:320–327PubMedCrossRefGoogle Scholar
- Tanimura A, Uchigashima M, Yamazaki M, Uesaka N, Mikuni T, Abe M, Hashimoto K, Watanabe M, Sakimura K, Kano M (2012) Synapse type-independent degradation of the endocannabinoid 2-arachidonoylglycerol after retrograde synaptic suppression. Proc Natl Acad Sci USA 109:12195–12200PubMedCentralPubMedCrossRefGoogle Scholar
- Yoshida T, Fukaya M, Uchigashima M, Miura E, Kamiya H, Kano M, Watanabe M (2006) Localization of diacylglycerol lipase-alpha around postsynaptic spine suggests close proximity between production site of an endocannabinoid, 2-arachidonoyl-glycerol, and presynaptic cannabinoid CB1 receptor. J Neurosci 26:4740–4751PubMedCrossRefGoogle Scholar
- Yoshida T, Uchigashima M, Yamasaki M, Katona I, Yamazaki M, Sakimura K, Kano M, Yoshioka M, Watanabe M (2011) Unique inhibitory synapse with particularly rich endocannabinoid signaling machinery on pyramidal neurons in basal amygdaloid nucleus. Proc Natl Acad Sci USA 108:3059–3064PubMedCentralPubMedCrossRefGoogle Scholar