CHANGES IN MUSCARINIC CHOLINERGIC, PCP, GABA(A), D-1, AND 5-HT2A RECEPTOR-BINDING, BUT NOT IN BENZODIAZEPINE RECEPTOR-BINDING IN THE BRAINSOF AGED RATS
T. Nabeshima et al., CHANGES IN MUSCARINIC CHOLINERGIC, PCP, GABA(A), D-1, AND 5-HT2A RECEPTOR-BINDING, BUT NOT IN BENZODIAZEPINE RECEPTOR-BINDING IN THE BRAINSOF AGED RATS, Life sciences, 55(20), 1994, pp. 1585-1593
Citations number
40
Categorie Soggetti
Biology,"Medicine, Research & Experimental","Pharmacology & Pharmacy
We used in vitro quantitative autoradiography to investigate changes i
n neurotransmitter receptor binding, including muscarinic cholinergic,
PCP, GABA(A), benzodiazepine, D-1 and 5-HT2A receptor, in the brains
of aged rats, compared with such binding in young rats. Scatchard anal
ysis revealed that the maximal number of binding sites for [H-3]quinuc
lidinyl benzilate (QNB) in the caudate/putamen and accumbens was signi
ficantly decreased in aged rats compared with young rats, while its af
finity remained unchanged. The specific binding of [H-3]N-(1-[2-thieny
l]cyclohexyl)3,4-piperidine (TCP) for the ion channels coupled with N-
methyl-D-aspartate receptors in the caudate/putamen and hippocampus wa
s significantly decreased in aged rats compared with young rats. The [
H-3]muscimol binding in aged rats was decreased in all brain regions e
xamined compared with that in young rats, whereas [H-3]flunitrazepam b
inding was not changed in any brain regions. The [H-3]SCH23390 binding
for dopamine D-1 receptors was significantly increased in the parieta
l cortex, but decreased in the caudate/putamen and accumbens of aged r
ats compared with that in young rats. The [H-3]ketanserin binding for
5-HT2A receptors in the cortex and accumbens was significantly decreas
ed in aged rats compared with young rats. These results suggest that u
neven changes in receptors for various neurotransmitters throughout th
e brain may be responsible for the decline of brain function in aged r
ats.