Effects of hippocampal kainic acid lesions on striatolimbic dopamine D1-, D2-, and D4-like receptors.
Changes in D1-, D2- and D4-like dopamine receptor binding in rat caudate-putamen, nucleus accumbens and hippocampus were examined by quantitative in vitro receptor autoradiography after unilateral injections of kainic acid into hippocampus to degenerate local intrinsic neurons and remove hippocampal-striatal projections. Radioligands were: [3H]SCH-23390 for D1-like (D1/D5) receptors, [3H]nemonapride alone for D2-like (D2/D3/D4) receptors and with 300 nM S[-]-raclopride and other masking agents for D4-like receptors. Kainic acid injections produced massive local hippocampal losses of D1-like (75%), D2-like (77%) and D4-like (79%) receptor binding but did not significantly alter D1-, D2- or D4-like receptor density in caudate-putamen or nucleus accumbens. Most D1-, D2- and D4-like receptors in rat hippocampus evidently arise on intrinsic postsynaptic neurons whereas none was detected on presynaptic terminals of hippocampal-striatal afferents innervating the striatal complex.
Mailman Research Center, McLean Division of Massachusetts General Hospital, Belmont 02178, USA.
F I
FI
Tarazi
A
A
Campbell
R J
RJ
Baldessarini
D000818:Animals; D001345:Autoradiography; D002421:Caudate Nucleus / Q000187:drug effects / Q000378:metabolism; D003342:Corpus Striatum / Q000187:drug effects* / Q000378:metabolism; D018691:Excitatory Amino Acid Antagonists / Q000633:toxicity*; D006624:Hippocampus / Q000187:drug effects* / Q000378:metabolism; D007608:Kainic Acid / Q000633:toxicity*; D008032:Limbic System / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D009714:Nucleus Accumbens / Q000187:drug effects / Q000378:metabolism; D011699:Putamen / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D017447:Receptors, Dopamine D1 / Q000378:metabolism*; D017448:Receptors, Dopamine D2 / Q000378:metabolism*; D050637:Receptors, Dopamine D3; D050638:Receptors, Dopamine D4; D050641:Receptors, Dopamine D5
C493595:Drd3 protein, rat; C493601:Drd4 protein, rat; C493607:Drd5 protein, rat; D018691:Excitatory Amino Acid Antagonists; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; D050637:Receptors, Dopamine D3; D050638:Receptors, Dopamine D4; D050641:Receptors, Dopamine D5; D007608:Kainic Acid