Activité, Système Moteur & Coordination
Douleur - Allodynie/Hyperalgésie Thermique
Douleur - Spontanée - Déficit de Posture
Douleur - Allodynie/Hyperalgésie Mécanique
Anxiété & Dépression
Apprentissage/Mémoire - Attention - Addiction
Physiologie & Recherche Respiratoire
Métabolisme & Prise Alimentaire
Douleur
Métabolisme
Système moteur
Neurodégénérescence
Thématiques transversales
Système musculaire
Functions de motricité générale
Troubles de l'humeur
Other disorders
Joints
Système Nerveux Central (SNC)
Système sensoriel
Authors
A. Charlet, A. Muller, A. Laux, V. Kemmel, A. Schweitzer et al.
Lab
Centre National de la Recherche Scientifique et Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg, France.
Journal
Molecular Pain
Abstract
BACKGROUND: Mice deficient for the stable tubule only peptide (STOP) display altered dopaminergic neurotransmission associated with severe behavioural defects including disorganized locomotor activity. Endogenous morphine, which is present in nervous tissues and synthesized from dopamine, may contribute to these behavioral alterations since it is thought to play a role in normal and pathological neurotransmission. RESULTS: In this study, we showed that STOP brain structures, including cortex, hippocampus, cerebellum and spinal cord, contain high endogenous morphine amounts. The presence of elevated levels of morphine was associated with the presence of a higher density of mu opioid receptor with a higher affinity for morphine in STOP brains. Interestingly, STOP mice exhibited significantly lower nociceptive thresholds to thermal and mechanical stimulations. They also had abnormal behavioural responses to the administration of exogenous morphine and naloxone. Low dose of morphine (1 mg/kg, i.p.) produced a significant mechanical antinociception in STOP mice whereas it has no effect on wild-type mice. High concentration of naloxone (1 mg/kg) was pronociceptive for both mice strain, a lower concentration (0.1 mg/kg) was found to increase the mean mechanical nociceptive threshold only in the case of STOP mice. CONCLUSIONS: Together, our data show that STOP mice displayed elevated levels of endogenous morphine, as well as an increase of morphine receptor affinity and density in brain. This was correlated with hypernociception and impaired pharmacological sensitivity to mu opioid receptor ligands.
BIOSEB Instruments Used:
Von Frey Filaments (Bio-VF-M)
