Expression of muscarinic M1 and M2 receptors in the anterior cingulate cortex associated with neuropathic pain.
Eur J Pain
; 14(9): 901-10, 2010 Oct.
Article
in En
| MEDLINE
| ID: mdl-20304689
ABSTRACT
The anterior cingulate cortex (ACC) and muscarinic receptors modulate pain. This study investigates changes in the expression of muscarinic-1 and -2 receptors (M1R, M2R) in rats' ACC (cg1-rostral- and cg2-caudal) using a model of neuropathic pain by denervation, measured as autotomy score (AS) for 8 days. Changes were analysed with painful stimuli and with scopolamine into the ACC prior to this scheme. We used reverse transcriptase-polymerase chain reaction (RT-PCR) and immunofluorescence to determine M1R and M2R's mRNA and protein levels, respectively. Animals were divided in low, medium and high AS groups. Cg1 showed decreased mRNA levels for both M1R and M2R in the low AS group, as opposed to an increased expression in the medium and high AS groups. Both receptors correlated positively with AS in these groups. In the scopolamine-treated animals there was an increase in mRNA levels for both receptors in cg1, whereas in cg2, mRNA levels of M1R decreased in all the AS and scopolamine groups. The increased M2R mRNA in cg2 correlated with AS in the low, medium and high AS groups whereas all the scopolamine groups showed an increase. Immunoreactivity of the M2R in cg1 decreased in the medium AS group in comparison to controls but scopolamine treatment produced an increase in the medium scopolamine AS group compared to the medium AS group. The M1R in cg1 and both receptors in cg2 showed no immunoreactivity changes. These results highlight the role of the M2R in cg1 related to the degree of autotomy.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Pain
/
Scopolamine
/
Peripheral Nervous System Diseases
/
Muscarinic Antagonists
/
Receptor, Muscarinic M1
/
Receptor, Muscarinic M2
/
Disease Models, Animal
/
Gyrus Cinguli
Type of study:
Prognostic_studies
/
Risk_factors_studies
Limits:
Animals
Language:
En
Journal:
Eur J Pain
Journal subject:
NEUROLOGIA
/
PSICOFISIOLOGIA
Year:
2010
Document type:
Article
Affiliation country:
Mexico