Discovery of CB2
In situ hybridization
(Munro et al. 1993)
Discovery of CB2
Binding studies
(Munro et al. 1993)
Discovery of CB2
In situ hybridization
(Munro et al. 1993)
GPR55 a putative third cannabinoid receptor?
First described as a cannabinoid receptor in a patent by Astra-Zeneca in 2004
(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
Degradation
Accumulation of [3H] ethanolamide
following incubation with [3H]AEA
Fatty acid amido-hydrolase
(FAAH)
Accumulation of [3H] ethanolamide
or [3H] arachidonate in phopholipids
following incubation with [3H]AEA
(Di Marzo et al 1994)
Endocannabinoids’ inactivation system
Internalization
Time course of [3H]AEA accumulation
in neurons (circle) or astrocytes (square)
(Beltramo et al 1997)
Linewaver-Burk analysis of [3H]AEA
accumulation in neurons (B) and astrocytes (C)
Endocannabinoids’ inactivation system
Internalization
Inhibition of [3H]AEA
accumulation by AM404
(Beltramo et al 1997)
AEA inactivation
(Piomelli 2003)
AEA inactivation
Fatty acid amide hydrolase (FAAH)
Cycloxygenase-2 (COX-2),
12- and 15-lipoxygenases (LOXs)
Cytochrome P450 (P450)
(Giuffrida and McMahon 2009)
2-AG inactivation
AEA and 2-AG internalization occur through
a substantially common mechanism
Monoacylglycerol lipase (MAGL) is considered
the major enzyme responsible for 2-AG metabolism
The endocannabinoid system
PLC
NAT
DAG
NAPE
PE-PC
FAAH
PLD
PIPX
MAGL
DGL
Endocannabinoids
uptake
uptake
Endocannabinoids
(AEA, 2-AG, noladin ehter, virodhamine, NADA)
Ca 2+
CB2
Gi/o
+/-
-
?
K
+
-
-
CB3
CB1
Gi/o
Gα12-13?
SMase
AC
-
+
ceramide
ATP
cAMP
NFkappaB
Raf-1
+
MAPK
JNK
?
Cannabinoid system physiological effects
•
•
•
•
•
•
•
Motor impairement
Memory impairement
Catalepsy
Temperature decrease
Analgesia
Pressure modification
Immune suppression/stimulation