UNIVERSITA'di

BOLOGNA

S. ORSOLAMALPIGHI

LA CANAPA E LO STIMOLODELLA FAME:

STORIA DI AGONISMI ED ANTAGONISMI

Dr. Uberto PagottoUnità Operativa di Endocrinologia

Dip. Medicina Int. e GastroenterologiaOspedale S.Orsola-Malpighi

Bologna

The first written evidence of medical use of cannabis

sativa comes from China some 5000 years ago

The drug was introduced in

Europe by Napoleon

Bonaparte’s troops when

returning from Egypt Nowadays marijuana and its

derivatives have become the

most widely consumed illegal

drugs in western countries

1964 isolation of 9-THC (Gaoni and Mechoulam)

The discovery of Cb receptors and their endogenous ligands

suggested the existence of an

Endogenous Cannabinoid System

Both receptors belong to the G protein coupled receptor superfamily

Ion channels

Adenylate-cyclase

Intracellular signal-regulated kinases

1990 cloning of cannabinoid

receptor 1 (Cb1Cb1) (Matsuda et al.)

1993 cloning of a second cannabinoid

receptor (Cb2Cb2) (Munro et al.)

1992 purification of anandamideanandamide,

the first endogenous cannabinoid (Devane et al.)

Cb1 ligands

9-THC

Classical cannabinoids

8-THCCannabinolCannabidiolHU 210

Non classical cannabinoids CP-55,940CP-55,940

Aminoalkylindols WIN-55,212

Endocannabinoids Anandamide

2-Arachidonylglycerol

Cb1 selective Cb1 selective antagonistsantagonists

SR 141716A

AM 630

D9-TetrahydrocannabinolO

OH1964 O

OHNH

Anandamide

1992

CB1

1990

FeedingFeeding

NeuroprotectionPain perception

Locomotion

Rewarding

ThermoregulationBlood pressure

Sleep Learning & Memory

Antitumoral activity

Hormones modulation

Anorexigenic peptidesAnorexigenic peptides

• Corticotrophin-releasing hormone (CRH)

• -melanocyte-stimulating hormone (-MSH)

• Cocaine-and amphetamine regulated transcripts (CART)

Orexigenic peptidesOrexigenic peptides• Neuropeptide Y (NPY)

• Agouti-related protein (AgRP)

• Melanin-concentrating hormone (MCH)

• Orexins (Hypocretins)

• Ghrelin

Amygdala Hippocampus

Reward

GABA

DOPA DOPA

D2-R

HypothalamusVentral tegmental

region Nucleus Accumbens

Reward

enkephalin

enkephalin

DOPA

GABA

DOPA5-HT

D2-R

Blue: excitatory neurons Red: inhibitory neurons

Substantia Nigra

Role of Reward System in feeding behavior in the

mesocorticolimbic pathaways

IN 1985, THE USE OF 9-THC (DRONABINOL) WAS APPROVED BY FDA FOR TREATMENT OF

CANCER-CHEMOTHERAPY INDUCED NAUSEA AND VOMITING REFRACTORY TO OTHER

AGENTS

Number of subjects

8 Marijuana- placebo

9 Placebo- marijuana

Average gain during Marijuana

week

Average loss during Placebo

week

0.69

0.39

2.10

1.11

Average weight loss or gain during placebo and treatment periods with 9-THC (2.5 mg or 5.0 mg per os, twice per day, for 2 weeks)

Regelson et al.

IN 1992, DRONABINOL WAS THE FIRST DRUG IN 1992, DRONABINOL WAS THE FIRST DRUG APPROVED BY FDA FOR THE TREATMENT OF APPROVED BY FDA FOR THE TREATMENT OF

ANOREXIA AND WEIGHT LOSS IN AIDS PATIENTS...ANOREXIA AND WEIGHT LOSS IN AIDS PATIENTS...

Mean change in weight from baseline, evaluable AIDS patients

Mean change in weight from baseline, evaluable AIDS patients. Excludes

patients with moderate, severe, or life-threatening drug- nonrelated adverse

events

Beal et al, 1995Beal et al, 1995

Mea

n W

eigh

t ch

ange

(K

g)

Dronabinol

Placebo

-0.5

0.0

-0.1

-0.2

-0.3

-0.4

0.2

0.1

0.3

Day 0 Day 14 Day 28 Day 42

Mea

n W

eigh

t ch

ange

(K

g)

Day 42-0.5

0.5

0.0

1.0

1.5

Day 0 Day 14 Day 28

Dronabinol

Placebo

STUDIES SUPPORT LONG-TERM, SAFE USE OF DRONABINOL FOR ANOREXIA AND CACHEXIA IN

AIDS PATIENTS

10

20

30

40

% p

atie

nts

wit

h a

t le

ast

2Kg

BW

gai

n

1 6 12

month

*

Dronabinol 2.5mg os

Placebo

(Beal et al., 1997)

DRONABINOL WAS TESTED ALSO IN ALZHEIMER PATIENTS

15 PATIENTS WERE TREATED FOR 6 WEEKS WITH PLACEBO AND 6 WEEKS WITH DRONABINOL

THE RESULTS WERE…..”BODY WEIGHT OF STUDY SUBJECTS

INCREASED MORE DURING THE DRONABINOL TREATMENT

THAN DURING THE PLACEBO PERIODS..”

Volicer L et al. 1997

9-THC +SRSR141716

2-h

ours

foo

d in

tak

e (g

)

2

4

6

8

***

*

†††

10

0 0.05 0.1 0.5 1

SR141716 mg/Kg s.c.

******

Reversal of 9-THChyperphagia in pre-fed rats by CB1 selective antagonist SR141716 (Williams et al, 2002)

Hyperphagia in pre-fed rats following oral 9-THC

(Williams et al, 1998)

8

2

4

6

0

2-h

ours

foo

d in

tak

e (g

) *

*

0.06

3

0.12

5

0.25 0.5 1 2

*

9-THC mg/Kg

The selective Cb1 antagonist, SR 141716A, reduces dose-dependently sucrose and ethanol intake in rodents

Arnone et al, 1997

SR 141716

Sucrose pellets

(rats)

Sucrose solution

(rats)

NPY-induced sucrose drinking

(rats)

Ethanol solution

(mice)

vehicle 3.1 0.4 28.3 5.0 8.1 1.7 1.9 0.1

0.3 mg/Kg 2.1 0.2 16.1 3.9 3.6 1.2† 1.3 0.2

1 mg/Kg 1.6 0.2** 7.4 2.8** 1.2 0.4†† 1.1 0.2**

3 mg/Kg 1.0 0.4** 8.6 2.9** n.d. 1.0 0.2**

If you want a knockout...

The conditional mutagenesis

CRE/lox P system

Gene targeting

Feeding behavior

CB1 Null-mutation

Breeding

CB1+/+ CB1-/-

Age (week)2 4 6 8 10 12 14 16

bod

y w

eigh

t (g

)

5

10

15

20

25

30

*

** * * * * *

* *

CB1-/- mice show decreased body weight and reduced fat mass

60

65

70

75

Lean mass

*

Fat mass

% o

f b

ody

wei

ght

5

10

15

CB1+/+

CB1-/-

**

% o

f b

ody

wei

ght

T T

T

T

B

B

CB1+/+

CB1-/-

Cota D. et al., J Clin Invest 2003

CRH/PVN

a

*

CART/PVN

b

CB1 transcripts are co-localized with mRNAs of hypothalamic neuropeptidesCB1 transcripts are co-localized with mRNAs of hypothalamic neuropeptides

Pre-pro-orexin/LHA

c

*

MCH/LHA

d

Cota D. et al., J Clin Invest 2003

Age (week)3 4 5 6

Cal

oric

inta

ke

(kca

l/d

ay)

5

10

15 YoungCB1+/+ CB1-/-

CB1CB1-/--/- lean phenotype is principally related to the decreased caloric intake lean phenotype is principally related to the decreased caloric intake

20 21 22

5

10

15

20

25

30

Cal

oric

inta

ke

(kca

l/d

ay)

Age (week)

AdultCB1+/+ CB1-/-

Bod

y w

eigh

t (g

)

5

10

15

20

25

Age (week)3 4 5 6

** * *** * **** *** *** ** *

† † † † † † † †† † † † †CB1+/+ pair-fed

CB1+/+ CB1-/-

20 21 2215

20

25

30

35

40

45

Age (week)

* * * * * * * * * * * * * * * * * *

Bod

y w

eigh

t (g

)

Cota D. et al., J Clin Invest 2003

0

100

200

300

400

CT WIN WIN+SR SR

LP

L a

ctiv

ity

(%

of

con

trol

) *M CB1

+/+

Actin

1.0

0.5CB1

CB1

-/-

NC NC

Hip

poH 2

O

White adipose tissue may represent White adipose tissue may represent a novel peripheral target for a novel peripheral target for

cannabinoid actioncannabinoid action

Cota D. et al., J Clin Invest 2003

We confirm that the cannabinoid system is strongly involved in the body weight regulation

I conclusions

• CB1ko mice are lighter and leaner than their wt controls

• CB1ko mice are not different in energy expenditure, body temperature and locomotor activity from their

wt controls

• Pairfeeding studies using young animals indicate a main role of central orexigenic drive in body weight

regulation, however in adults also a food-intake-independent mechanism contributes to the lean

phenotype

•Higher expression of CRH mRNA in PVN of CB1ko mice fed ad libitum,lower expression of CART mRNA in LHA and DMN of CB1ko mice fed ad libitum

• CB1 is expressed in adipose tissue and stimulates lipogenesis

•CRH, CART, Pre-pro-orexin, MCH co-expression and CB1have been found in hypothalamus of wt fed ad libitum

We confirm that the cannabinoid system is strongly involved in the body weight regulation

II conclusions

Endogenous Cannabinoid System seems to be an ideal target for the treatment of eating disorders and obesity

Hypothalamic action of CB1 antagonists

may modulate neuropeptide network controlling food intake

CB1 antagonists acting in the limbic

system may decrease the rewarding

property of food

Blockade of gastroenteric CB1

might contribute to the therapy by

modulating feeding-related peripheral

signals

Anti-obesity action Anti-obesity action of CB1 of CB1 antagonists

could involve could involve metabolic processes metabolic processes and directly target and directly target

adipose tissueadipose tissue

The cannabinoid system is involved in several physiological functions and

might be related to a general stress-recovery system.

Such a variety of effects was concisely summarized by a recent statement by Di Marzo:

Di Marzo et al. Trends Neurosc, 1998

“…..FEEL LESS PAIN, CONTROL YOUR MOVEMENT,

RELAX, EAT, FORGET, SLEEP AND PROTECT.”