| First Author | Takahashi KA | Year | 2006 |
| Journal | Neuroscience | Volume | 139 |
| Issue | 3 | Pages | 795-802 |
| PubMed ID | 16527424 | Mgi Jnum | J:108854 |
| Mgi Id | MGI:3625203 | Doi | 10.1016/j.neuroscience.2006.01.024 |
| Citation | Takahashi KA, et al. (2006) The CB1 cannabinoid receptor mediates glutamatergic synaptic suppression in the hippocampus. Neuroscience 139(3):795-802 |
| abstractText | Cannabinoids have profound effects on synaptic function and behavior. Of the two cloned cannabinoid receptors, cannabinoid receptor 1 (CB1) is widely distributed in the CNS and accounts for most of the neurological effects of cannabinoids, while cannabinoid receptor 2 (CB2) expression in the CNS is very limited. The presence of additional receptors [i.e. cannabinoid receptor 3 (CB3)] is suggested by growing evidence of cannabinoid effects that are not mediated by CB1 or CB2. The most direct functional evidence for a CB3 comes from a study in hippocampus where deletion of CB1 was shown to have no effect on cannabinoid-mediated suppression of the excitatory synapse between Schaffer collateral/commissural fibers and CA1 pyramidal cells [Novel cannabinoid-sensitive receptor mediates inhibition of glutamatergic synaptic transmission in the hippocampus. Neuroscience 106:1-4]. In contrast, we report here that in extracellular field recordings, the cannabinoid agonist WIN 55,212-2 (5 microM) had no effect on Schaffer collateral/commissural fiber-CA1 pyramidal cell (Sch-CA1) synaptic transmission in slices from two independently made cannabinoid receptor 1-/- lines [Zimmer et al 1999 and Ledent et al 1999] while strongly suppressing Sch-CA1 synaptic transmission in CB1+/+ mice of the background strains. Also, we observed robust cannabinoid-mediated suppression of the Sch-CA1 synapse in pure C57BL/6 mice, contradicting a recent report that cannabinoid suppression of this synapse is absent in this strain [Hoffman AF, Macgill AM, Smith D, Oz M, Lupica CR (2005) Species and strain differences in the expression of a novel glutamate-modulating cannabinoid receptor in the rodent hippocampus. Eur J Neurosci 22:2387-2391]. Our results strongly suggest that cannabinoid-induced suppression of the Sch-CA1 synapse is mediated by CB1. Non-canonical cannabinoid receptors do not seem to play a major role in inhibiting transmitter release at this synapse. |
