Discovery of CB2

Discovery of CB2

(Munro et al. 1993)

In situ hybridization

Discovery of CB2

(Munro et al. 1993)

Binding studies

Discovery of CB2

(Munro et al. 1993)

In situ hybridization

GPR55 a putative third cannabinoid receptor?

First described as a cannabinoid receptor in a patent by Astra-Zeneca in 2004

(Brown 2007)(Brown 2007)

GPR55 a putative third cannabinoid receptor?

(Brown 2007)

Discovery of endogenous cannabinoids(Devane et al. 1992)

• Screening for endogenous cannabinoid ligands using porcine brain

• Identification of an arachidonic acid derivative (arachidonylethanolamide) that binds to CB receptor

• This arachidonic acid derivative inhibited in a concentration dependent manner the binding of radiolabelled cannabinoid to synaptosomal membrane.

• The compound is named Anandamide from the Sanskrit ananda (bliss, delight)

Endogenous cannabinoids

Mechanisms of anandamide formation

(Cadas et al 1996)

Mechanisms of 2-AG formation

(Piomelli 2003)

Endocannabinoids’ inactivation system

Accumulation of [3H] ethanolamide following incubation with [3H]AEA

Fatty acid amido-hydrolase(FAAH)

Degradation

(Di Marzo et al 1994)

Accumulation of [3H] ethanolamideor [3H] arachidonate in phopholipidsfollowing incubation with [3H]AEA

(Beltramo et al 1997)

Time course of [3H]AEA accumulation in neurons (circle) or astrocytes (square)

Linewaver-Burk analysis of [3H]AEA accumulation in neurons (B) and astrocytes (C)

Internalization

Endocannabinoids’ inactivation system

(Beltramo et al 1997)

Inhibition of [3H]AEA accumulation by AM404

Internalization

Endocannabinoids’ inactivation system

AEA inactivation

(Piomelli 2003)

AEA inactivation

(Giuffrida and McMahon 2009)

Fatty acid amide hydrolase (FAAH) Cycloxygenase-2 (COX-2), 12- and 15-lipoxygenases (LOXs)Cytochrome P450 (P450)

2-AG inactivation

Monoacylglycerol lipase (MAGL) is consideredthe major enzyme responsible for 2-AG metabolism

AEA and 2-AG internalization occur througha substantially common mechanism

The endocannabinoid systemNAT

NAPE

PLD

PLC

DAG

DGL

Endocannabinoids

PE-PC

PIPX

Endocannabinoids(AEA, 2-AG, noladin ehter, virodhamine, NADA)

uptake

FAAH MAGL

uptake

NFkappaB

AC-

ATP cAMP

SMase

ceramide

Raf-1

JNK

Ca2+K

+

- +

+/--

-

CB3

Gα12-13?

+MAPK

?

?CB2

Gi/o Gi/oCB1

Cannabinoid system physiological effects

• Motor impairement

• Memory impairement

• Catalepsy

• Temperature decrease

• Analgesia

• Pressure modification

• Immune suppression/stimulation