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