RefDoc
Haut

Faire une nouvelle recherche
Make a new search
Lancer la recherche


Titre du document / Document title

The spontaneously hypertensive-rat as an animal model of ADHD: evidence for impulsive and non-impulsive subpopulations

Auteur(s) / Author(s)

ADRIANI Walter (1) ; CAPRIOLI Antonio (2) ; GRANSTREM Oleg (3 4) ; CARLI Mirjana (5) ; LAVIOLA Giovanni (1) ;

Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)

(1) Behavioural Pathophysiology Section, Lab FOS, Department of Cell Biology and Neuroscience, Istituto Superiore di Sanita', viale Regina Elena 299, Roma 00161, ITALIE
(2) Behavioural Pharmacology Lab, Sigma-Tau SpA, Pomezia, ITALIE
(3) Department of Chemistry, Emory University, Atlanta, GA, ETATS-UNIS
(4) Department of Neurology and Neurosurgery I.P. Pavolov state medical university, St. Petersburg, RUSSIE, FEDERATION DE
(5) Department of Neuroscience, 'Mario Negri' Institute, Milano, ITALIE

Résumé / Abstract

Attention-deficit hyperactivity disorder (ADHD) is a neuropsychiatric syndrome, affecting human infants and adolescents. Two main behavioural features are reported: (1) impaired attention and (2) an impulsive-hyperactive behavioural trait. The latter has been studied in a series of experiments, using the spontaneously hypertensive-rat (SHR) strain (which is regarded as a validated animal model for ADHD) in operant tasks. Food-restricted SHRs and their Wistar-Kyoto (WKY) controls were tested during adolescence (i.e. post-natal days 30-45), in operant chambers provided with two nose-poking holes. Nose-poking in one hole (H1) resulted in the immediate delivery of a small amount of food, whereas nose-poking in the other hole (H5) delivered a larger amount of food after a delay, which was increased progressively each day (0-100 s) As expected, all animals showed a shift in preference from the large (H5) to the immediate (H I ) reinforcer as the delay length increased. Impulsivity can be measured by the steepness of this preference-delay curve. The two strains differed in home-cage circadian activity, SHRs being more active than WKYs at several time-points. During the test for impulsivity, inter-individual differences were completely absent in the WKY strain, whereas a huge inter-individual variability was evident for SHRs. On the basis of the median value of average hole-preference, we found an 'impulsive' SHR subgroup, with a very quick shift towards the H I hole, and a flat-slope ('non-impulsive') SHR subgroup, with little or no shift The impulsive subpopulation also presented reduced noradrenaline levels in both cingulated and medial-frontal cortex, as well as reduced serotonin turnover in the latter. Also, cannabinoid CB 1 receptor density resulted significantly lower in the prefrontal cortex of impulsive SHRs, when compared to both the non-impulsive subgroup and control WKYs. Interestingly, acute administration of a cannabinoid agonist (WIN 55,212, 2 mg/kg s.c.) normalized the impulsive behavioural profile, without any effect on WKY rats. Thus, two distinct subpopulations, differing for impulsive behaviour and specific neurochemical parameters, were evidenced within adolescent SHRs. These results support the notion that a reduced cortical density of cannabinoid CB receptors is associated with enhanced impulsivity. This behavioural trait can be positively modulated by administration of a cannabinoid agonist. Present results confirm and extend previous literature, indicating that adolescent SHRs represent a suitable animal model for the preclinical investigation of the early-onset ADHD syndrome.

Revue / Journal Title

Neuroscience and biobehavioral reviews    ISSN  0149-7634 

Source / Source

Congrès
INABIS 2002 Internet World Congress of Biomedical Sciences No7, Lima , PEROU (14/04/2002)
2003, vol. 27, no 7 (110 p.)  [Document : 13 p.] (76 ref.), pp. 639-651 [13 page(s) (article)]

Langue / Language

Anglais

Editeur / Publisher

Elsevier, Kidlington, ROYAUME-UNI  (1978) (Revue)

Mots-clés anglais / English Keywords

Central nervous system

;

Encephalon

;

Biological rhythm

;

Acquisition process

;

Learning

;

Vertebrata

;

Mammalia

;

Rodentia

;

Neurotransmission

;

CB1 cannabinoid receptor

;

Young animal

;

Rat

;

Animal

;

Frontal cortex

;

Circadian rhythm

;

Positive reinforcement

;

Instrumental conditioning

;

Animal model

;

Impulsivity

;

Hyperactivity

;

Attentional disorder

;

Mots-clés français / French Keywords

Système nerveux central

;

Encéphale

;

Rythme biologique

;

Processus acquisition

;

Apprentissage

;

Vertebrata

;

Mammalia

;

Rodentia

;

Rat SHR

;

Neurotransmission

;

Récepteur cannabinoïde CB1

;

Animal jeune

;

Rat

;

Animal

;

Cortex frontal

;

Rythme circadien

;

Renforcement positif

;

Conditionnement instrumental

;

Modèle animal

;

Impulsivité

;

Hyperactivité

;

Trouble attention

;

Mots-clés espagnols / Spanish Keywords

Sistema nervioso central

;

Encéfalo

;

Ritmo biológico

;

Proceso adquisición

;

Aprendizaje

;

Vertebrata

;

Mammalia

;

Rodentia

;

Neurotransmisión

;

Receptor canabinoide CB1

;

Animal joven

;

Rata

;

Animal

;

Corteza frontal

;

Ritmo circadiano

;

Reforzamiento positivo

;

Condicionamiento instrumental

;

Modelo animal

;

Impulsividad

;

Hiperactividad

;

Trastorno atención

;

Localisation / Location

INIST-CNRS, Cote INIST : 18046, 35400011487031.0060

Nº notice refdoc (ud4) : 15308720



Faire une nouvelle recherche
Make a new search
Lancer la recherche
Bas