Postnatal development of cannabinoid receptor type 1 expression in rodent somatosensory cortex

• Published in: Neuroscience Vol. 145; no. 1; pp. 279 - 287
• Main Authors: Deshmukh, S, Onozuka, K, Bender, K.J, Bender, V.A, Lutz, B, Mackie, K, Feldman, D.E
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 02.03.2007; Elsevier
• Subjects: Age Factors; Animals; Animals, Newborn; axons; barrel; Biological and medical sciences; Brain Mapping; cannabinoid; Female; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Developmental - physiology; Immunohistochemistry; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Neurology; Rats; Rats, Long-Evans; Receptor, Cannabinoid, CB1 - deficiency; Receptor, Cannabinoid, CB1 - metabolism; sensory map; septa; Somatosensory Cortex - growth & development; Somatosensory Cortex - metabolism; Somesthesis and somesthetic pathways (proprioception, exteroception, nociception); interoception; electrolocation. Sensory receptors; Vertebrates: nervous system and sense organs; whisker; endocannabinoid; eCB; cannabinoid; whisker; 3,3′-diaminobenzidine; phosphate buffer; L; septa; P; axons; primary somatosensory cortex; Tris-buffered saline; cytochrome oxidase; postnatal day; depolarization-induced suppression of inhibition; DSI; barrel; sensory map; DAB; TBS; CO; cannabinoid receptor type 1; cortical layer; PB; CB1; S1; Central nervous system; Rodentia; Axon; Cannabinoid; Postnatal development; Encephalon; Somatosensory cortex; Vertebrata; Mammalia; Somesthetic pathway; Cannabinoid receptor
• ISSN: 0306-4522; 1873-7544
• DOI: 10.1016/j.neuroscience.2006.11.033

Abstract Endocannabinoids are powerful modulators of synaptic transmission that act on presynaptic cannabinoid receptors. Cannabinoid receptor type 1 (CB1) is the dominant receptor in the CNS, and is present in many brain regions, including sensory cortex. To investigate the potential role of CB1 receptors in cortical development, we examined the developmental expression of CB1 in rodent primary somatosensory (barrel) cortex, using immunohistochemistry with a CB1-specific antibody. We found that before postnatal day (P) 6, CB1 receptor staining was present exclusively in the cortical white matter, and that CB1 staining appeared in the gray matter between P6 and P20 in a specific laminar pattern. CB1 staining was confined to axons, and was most prominent in cortical layers 2/3, 5a, and 6. CB1 null (−/−) mice showed altered anatomical barrel maps in layer 4, with enlarged inter-barrel septa, but normal barrel size. These results indicate that CB1 receptors are present in early postnatal development and influence development of sensory maps.