Neuroscientists discover previously unknown function of cannabinoid receptor

Neuroscientists discover previously unknown function of cannabinoid receptor

“Previously Unknown Function of a Cannabinoid Receptor Identified.  Study could improve our insights into brain diseases.” http://neurosciencenews.com/cb2-cannabinoid-receptor-hippocampus-4147/

“In the brain, there is a delicate interplay of signaling substances and cellular activity. Scientists have now identified another key player within this ensemble. In a laboratory study they found that the ‘cannabinoid type 2 receptor’ influences information processing inside the hippocampus. The research results might help advance our understanding of schizophrenia and Alzheimer’s, say the authors.”  https://www.sciencedaily.com/releases/2016/05/160502111228.htm

“The cannabinoid type 2 receptor – also called “CB2 receptor” – is a special membrane protein. Its function is to receive chemical signals that control cellular activity. “Until now, this receptor was considered part of the immune system without function in nerve cells. However, our study shows that it also plays an important role in the signal processing of the brain,” explains Professor Dietmar Schmitz, Speaker for the DZNE-Site Berlin and Director of the Neuroscience Research Center of the Charité (NWFZ/NeuroCure).”  https://scienceblog.com/483935/neuroscientists-discover-previously-unknown-function-cannabinoid-receptor/

 

Cannabinoid Type 2 Receptors Mediate a Cell Type-Specific Plasticity in the Hippocampus

“Endocannabinoids (eCBs) exert major control over neuronal activity by activating cannabinoid receptors (CBRs).

The functionality of the eCB system is primarily ascribed to the well-documented retrograde activation of presynaptic CB1Rs.

We find that action potential-driven eCB release leads to a long-lasting membrane potential hyperpolarization in hippocampal principal cells that is independent of CB1Rs.

The hyperpolarization, which is specific to CA3 and CA2 pyramidal cells (PCs), depends on the activation of neuronal CB2Rs, as shown by a combined pharmacogenetic and immunohistochemical approach.

Upon activation, they modulate the activity of the sodium-bicarbonate co-transporter, leading to a hyperpolarization of the neuron.

CB2R activation occurred in a purely self-regulatory manner, robustly altered the input/output function of CA3 PCs, and modulated gamma oscillations in vivo.

To conclude, we describe a cell type-specific plasticity mechanism in the hippocampus that provides evidence for the neuronal expression of CB2Rs and emphasizes their importance in basic neuronal transmission.”

http://www.cell.com/neuron/abstract/S0896-6273(16)30025-3

Cannabidiol attenuates catalepsy induced by distinct pharmacological mechanisms via 5-HT1A receptor activation in mice.

“Cannabidiol (CBD) is a non-psychotomimetic compound from Cannabis sativa plant that produces antipsychotic effects in rodents and humans.

It also reverses L-dopa-induced psychotic symptoms and improves motor function in Parkinson’s patients. This latter effect raised the possibility that CBD could have beneficial effects on motor related striatal disorders.

To investigate this possibility we evaluated if CBD would prevent catalepsy induced by drugs with distinct pharmacological mechanisms.

These findings indicate that CBD can attenuate catalepsy caused by different mechanisms (D2 blockade, NOS inhibition and CB1 agonism) via 5-HT1A receptor activation, suggesting that it could be useful in the treatment of striatal disorders.”

http://www.ncbi.nlm.nih.gov/pubmed/23791616

Cannabidiol attenuates haloperidol-induced catalepsy and c-Fos protein expression in the dorsolateral striatum via 5-HT1A receptors in mice.

“Cannabidiol (CBD) is a major non-psychoactive compound from Cannabis sativa plant.

Given that CBD reduces psychotic symptoms without inducing extrapyramidal motor side-effects in animal models and schizophrenia patients, it has been proposed to act as an atypical antipsychotic.

In addition, CBD reduced catalepsy induced by drugs with distinct pharmacological mechanisms, including the typical antipsychotic haloperidol.

Altogether, these results suggest that CBD acts in the dorsal striatum to improve haloperidol-induced catalepsy via postsynaptic 5-HT1A receptors.”

http://www.ncbi.nlm.nih.gov/pubmed/27131780