Intoxicación por Cannabis sativa

en caninos

Dr. Luis Delucchi

1

2

Ananda

Canabinoides vegetales

Mas de 400 compuestos

Tetrahidrocanabinol= THC

Otros canabinoides naturales

supported the hypothesis that D9-THC is the main psycho-tropic constituent of cannabis. The possibility of using rats ormice instead of dogs or monkeys was also explored and thisapproach led to the development of several new in vivobioassays. These included four tests that were later combinedto form what came to be known as the ‘mouse tetrad’ (seebelow). In one of these bioassays, the ring test, mice are placedacross an elevated horizontal ring and the proportion of timethey remain immobile/cataleptic (immobility index) is mon-itored over a 5-min period (Pertwee, 1972). Cannabis andpsychoactive cannabinoids such as D9-THC cause the im-mobility index to increase in a dose-related manner. Thisbioassay was based on an observation by Loewe (1946) thatTHC extracted from cannabis resin induced a cataleptic statein the mouse that is ‘best manifested when the animal is placed

prone upon an arrangement (brim of a beaker or two parallelwires) for supporting it only at the thigh and jaws’. Eventually,in vitro assays for cannabinoids were also developed and it wastwo of these in particular, a bioassay that measures adenylatecyclase activity and a radioligand binding assay, that providedconclusive evidence for the existence of the cannabinoid CB1

receptor.

The discovery of cannabinoid receptors

Early indications of the existence of cannabinoid receptorscame from reports firstly, that the pharmacological activityof psychotropic cannabinoids is significantly influenced bychemical structure, secondly, that cannabinoids with chiral

O

OH

∆8-THC

Cannabinol

O

OH

O

OH

61' 5'3'

∆9-THC

1

2

3

45

7

89

10

136a 10a

11

10b

12

O

OH

∆6a,10a-THC Synhexyl

O

OH

O

OH

∆9-THCV

OH

OH

Cannabidiol

2’3’

4’

5’

5

61

2

4 3

7

1’

8

1’' 5’'3’'

6’

Figure 1 The structures of five plant cannabinoids (phytocannabinoids), D9-tetrahydrocannabinol (D9-THC), D8-THC,cannabidiol (CBD), cannabinol (CBN) and D9-tetrahydrocannabivarin (D9-THCV), and of two synthetic cannabinoids, D6a,10a-THC and synhexyl.

R.G. Pertwee Cannabinoid pharmacology S165

British Journal of Pharmacology vol 147 (S1)

Inhalación: 50% THC

Ingesta: 20 %

Signos clínicos aparecen 60 minutos post ingesta

Dosis letal mínima oral : 3 gr/kg THC

1000 ＞que la necesaria para signos clínicos9

Liposoluble, ingesta grasa ⇧ absorción

Metabolizado en el hígado, P450

Tiene re circulación entero-hepática

15% orina

85% heces

En 5 días se excreta el 80%

Vías de intoxicación

Alimentos preparados

Usos médicos

Receptores✦ CB1: ganglios basales, sustancia nigra, globus pallidus,

cerebelo y corteza frontal. Inhiben neuromediadores

✦ CB2: En macrófagos, timo, terminaciones de nervios periféricos Respuesta del sistema inmune e inflamación.

Signos clínicos bifásicos

DiagnósticoAnálisis químico de orina (CG, HPLC)

Test rápido o Screening test

Tratamiento

TratamientoCarbón activado: 1 a 2 gr/kg c/ 8 hs

Diazepam: 0,25 a 0,5 mg/kg

Clorpromazina: 0,5 a 1 mg/kg

Fluidoterapia a temperatura corporal

Antieméticos: Maropitant 1mg/kg s/c , 24 hs

Abrigo

Gracias!!

Unidad de Neurología Departamento

de Patología y Clínica de Pequeños Animales neuropeq@fvet.edu.uy