Muscarinic receptor changes in the gerbil thalamus during aging.
Here we studied muscarinic receptors in the gerbil thalamus at 8 different ages - from 6 to 36 months - using receptor and functional autoradiography. The pharmacological profile inhibiting [(3)H]N-methyl scopolamine ([(3)H]NMS) binding with 50 and 200 nM pirenzepine, 30 nM pFHHSiD and 100 nM AF-DX 116 revealed the predominance of the M(2) muscarinic subtype in the thalamic nuclei studied, mainly in the anteroventral, anteromedial and paraventricular thalamic nuclei. These data correlated with the highest [(35)S]guanylyl-5'-O-(gamma-thio)-triphosphate ([(35)S]GTP gamma S) binding induced in these nuclei by the muscarinic agonist oxotremorine in functional autoradiographic assays. Significant aging-dependent increases in the functional response in these three nuclei were observed, but only the anteroventral and anteromedial thalamic nuclei showed aging-dependent increases in [(3)H]NMS binding. Since these nuclei exert relevant functions, in which cholinergic pathways are involved and acetylcholine release is reported to decrease during aging, we suggest that the anteroventral and anteromedial thalamic nuclei would play critical roles in the cholinergic transmission that require compensatory mechanisms during the aging process and that are not observed in other thalamic nuclei.
Departamento Farmacología, Facultad de Medicina, Universidad de Cantabria, Santander 39011, Spain.
Fuencisla
F
Pilar-Cuéllar
Miguel Angel
MA
Paniagua
Rebeca
R
Díez-Alarcia
Severiano
S
Dos Anjos
Sheyla
S
Montori
Carlos Cesar
CC
Pérez
Arsenio
A
Fernández-López
D000109:Acetylcholine / Q000378:metabolism*; D000375:Aging / Q000378:metabolism*; D000818:Animals; D020643:Anterior Thalamic Nuclei / Q000187:drug effects / Q000378:metabolism; D001667:Binding, Competitive / Q000187:drug effects / Q000502:physiology*; D005849:Gerbillinae; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000378:metabolism; D008297:Male; D018727:Muscarinic Antagonists / Q000378:metabolism; D009434:Neural Pathways / Q000187:drug effects / Q000378:metabolism; D010276:Parasympatholytics / Q000378:metabolism; D043585:Receptor, Muscarinic M2 / Q000187:drug effects / Q000378:metabolism; D011976:Receptors, Muscarinic / Q000187:drug effects / Q000378:metabolism*; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology*; D013788:Thalamus / Q000187:drug effects / Q000378:metabolism*
D018727:Muscarinic Antagonists; D010276:Parasympatholytics; D043585:Receptor, Muscarinic M2; D011976:Receptors, Muscarinic; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D000109:Acetylcholine