Differences in the regulation of acetylcholine release upon D2 dopamine and N-methyl-D-aspartate receptor activation between the striatal complex of reptiles and the neostriatum of rats.
Activation of the N-methyl-D-aspartate (NMDA) receptor increases and that of the D2 dopamine (DA) receptor inhibits the release of acetylcholine (ACh) from mammalian neostriatal tissue. Similar effects have been described in the ventral striatum of the rat, however, in the caudomedial part of the nucleus accumbens, D2 receptor activation does not inhibit the release of ACh. Likewise, the NMDA-induced stimulation of the release of ACh in this part of the striatum is much smaller. In the present study we demonstrated that in the striatal complex or striatum of reptiles D2 receptor activation did not result in an inhibition of the release of ACh, whereas the release of DA could be inhibited to a significant extent. These findings indicate that, although D2 receptors are present in the striatum of reptiles, these receptors do not regulate the release of ACh in this brain structure. We observed in the striatum of reptiles a potassium induced and calcium-dependent release of [3H]D-aspartate indicating a neurotransmitter role for aspartate or glutamate (GLU). However GLU and NMDA have only a marginal effect on the release of ACh in the striatum of the reptiles as compared to the effects in the neostriatum of the rat. It is concluded that with respect to the effects of D2 and NMDA receptor activation on the release of ACh, the striatum of reptiles bears most similarity to the caudomedial part of the nucleus accumbens.
Department of Anatomy, Medical Faculty, Free University, Amsterdam, The Netherlands.
J M
JM
Henselmans
P V
PV
Hoogland
J C
JC
Stoof
D000109:Acetylcholine / Q000502:physiology*; D000818:Animals; D001224:Aspartic Acid / Q000378:metabolism; D003342:Corpus Striatum / Q000187:drug effects / Q000502:physiology*; D004298:Dopamine / Q000378:metabolism; D015259:Dopamine Agents / Q000494:pharmacology*; D004873:Ergolines / Q000494:pharmacology*; D005260:Female; D066298:In Vitro Techniques; D008116:Lizards / Q000502:physiology*; D008297:Male; D016202:N-Methylaspartate / Q000494:pharmacology*; D019257:Quinpirole; D051381:Rats; D011919:Rats, Inbred Strains / Q000502:physiology*; D011954:Receptors, Dopamine / Q000187:drug effects / Q000502:physiology*; D017448:Receptors, Dopamine D2; D016194:Receptors, N-Methyl-D-Aspartate / Q000187:drug effects / Q000502:physiology*; D013045:Species Specificity; D014426:Turtles / Q000502:physiology*
D015259:Dopamine Agents; D004873:Ergolines; D011954:Receptors, Dopamine; D017448:Receptors, Dopamine D2; D016194:Receptors, N-Methyl-D-Aspartate; D019257:Quinpirole; D001224:Aspartic Acid; D016202:N-Methylaspartate; D000109:Acetylcholine; D004298:Dopamine