Striatal input- and rate-dependent effects of muscarinic receptors on pallidal firing.
The globus pallidus (GP) plays a key role in the overall basal ganglia (BG) activity. Despite evidence of cholinergic inputs to GP, their role in the spiking activity of GP neurons has not received attention. We examine the effect of local activation and blockade of muscarinic receptors (MRs) in the spontaneous firing of GP neurons both in normal and ipsilateral striatum-lesioned rats. We found that activation of MRs produces heterogeneous responses in both normal and ipsilateral striatum-lesioned rats: in normal rats the response evoked by MRs depends on the predrug basal firing rate; the inhibition evoked by MRs is higher in normal rats than in striatum-lesioned rats; the number of neurons that undergo inhibition is lower in striatum-lesioned rats than in normal rats. Our data suggest that modulation of MRs in the GP depends on the firing rate before their activation and on the integrity of the striato-pallidal pathway.
Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina, Instituto Politécnico Nacional, Plan de San Luis y Díaz Mirón, 11340 México, DF, Mexico. equerejeta@ipn.mx
Enrique
E
Querejeta
Alberto
A
Alatorre
Alain
A
Ríos
Rafael
R
Barrientos
Aldo
A
Oviedo-Chávez
Rosa Amalia
RA
Bobadilla-Lugo
Alfonso
A
Delgado
D000818:Animals; D001285:Atropine / Q000494:pharmacology; D018723:Bethanechol / Q000494:pharmacology; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism; D005917:Globus Pallidus / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D018721:Muscarinic Agonists / Q000494:pharmacology; D018727:Muscarinic Antagonists / Q000494:pharmacology; D010095:Oxotremorine / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D011976:Receptors, Muscarinic / Q000378:metabolism*
D018721:Muscarinic Agonists; D018727:Muscarinic Antagonists; D011976:Receptors, Muscarinic; D018723:Bethanechol; D010095:Oxotremorine; D001285:Atropine