A cell population that strongly expresses the CB1 cannabinoid receptor in the ependyma of the rat spinal cord

Abstract

The cells surrounding the central canal of the spinal cord are a source of stem/precursor cells that may give rise to neurons, astrocytes, or oligodendrocytes. However, they are a heterogeneous population that remains poorly understood. Here we describe a subpopulation characterized by their strong expression of the CB(1) cannabinoid receptor, oval/round soma, apical nucleus, a variable number of cilia (0, 1, or 2), and the presence of a single short and occasionally ramified basal process. These cells are mainly located in the lateral and dorsal central canal throughout the spinal cord. These CB(1)(HIGH) cells are closely related to the basal lamina labyrinths or fractones derived from subependymal microglia. In addition, CB(1)(HIGH) cells express some stem/precursor cell markers, including vimentin, nestin, Sox2, Sox9, and GLAST, but not others such as CD15 or GFAP. In addition, this cell population does not proliferate in the intact adult spinal cord, although up to 50% of these cells express the proliferation marker Ki67 in newly born rats or after a spinal cord contusion. The present findings contribute to our understanding of the spinal cord central canal structure and reveal the targets for endocannabinoids inside this neurogenic niche.

Neuroimmmune interactions of cannabinoids in neurogenesis: focus on interleukin-1β (IL-1β) signalling

“…In the adult spinal cord central canal, which harbours neurogenic potential, there is a subpopulation of ependymal cells expressing high levels of CB 1 receptors. This subpopulation may proliferate during postnatal development and after a spinal cord injury [26].…”

Progesterone Reduces Secondary Damage, Preserves White Matter, and Improves Locomotor Outcome after Spinal Cord Contusion

“…23,24 Briefly, animals were anesthetized with an intraperitoneal injection of sodium pentobarbital (45 mg/kg, Normon Veterinary Division, Madrid, Spain) and Xilagesic (2% xylazine, 10 mg/kg, Calier, Barcelona, Spain). Once the absence of reflexes had been checked, the rats were injected with a low dose of atropine (50 lg/kg body weight; Brown Medical, Barcelona, Spain) to reduce salivary and bronchial secretions and to avoid the induction of bradycardia and possible cardiac arrest by the surgery or xylazine.…”

Cannabinoids to treat spinal cord injury

“…However, CB 1 expression in sensory afferents is still under discussion: while some studies report low levels or absence of CB 1 in substance P, CGRP, isolectin B4, β-subunit of cholera toxin and TRPV1 terminals (Ong and Mackie, 1999;Farquhar-Smith et al, 2000;Salio et al, 2002a,b;Furuse et al, 2009;Pernia-Andrade et al, 2009), others show CB 1 expression in primary afferents coming from dorsal root ganglion neurons projecting to the upper layers of the dorsal horn and in DRG-derived large myelinated fibers, that project to deeper layers of the spinal cord (Salio et al, 2002a,b;Bridges et al, 2003;Nyilas et al, 2009;Veress et al, 2013). Additionally, CB 1 in the intact spinal cord is expressed by glial cells: astrocytes (Salio et al, 2002a, b;Hegyi et al, 2009), microglia (Hegyi et al, 2009), oligodendrocytes (Garcia-Ovejero et al, 2009) and a subpopulation of ependymal cells (Garcia-Ovejero et al, 2013).…”

“…The endocannabinoid system has also been involved in chicken spinal development, with a stage-specific upregulation of CB 1 , DAGL-α and MAGL (Watson et al, 2008); and in the control of spinal neurogenic niches, were CB 1 may play a role in the neurogenic niche of the adult rat spinal cord (Garcia-Ovejero et al, 2013) and neural progenitor fate (Sideris et al, 2012).…”