Toonen M, van Dijken H, Holstege J C, Ruigrok T J, Koekkoek S K, Hawkins R K, Teune T M, vd Burg J, De Zeeuw C I
Department of Anatomy, Erasmus University of Rotterdam, Netherlands.
Brain Res. 1998 Aug 17;802(1-2):267-73. doi: 10.1016/s0006-8993(98)00593-9.
The ventrolateral outgrowth of the inferior olive is involved in the control of compensatory eye movement responses to optokinetic stimuli about the horizontal axis that is perpendicular to the ipsilateral anterior semicircular canal. Combining immunocytochemistry with retrograde tracing of WGA-BSA-gold, we demonstrated in the present study that this olivary subnucleus receives a substantial dopaminergic input, and that the prerubral parafascicular area and its surrounding regions form the sole source of this input. In addition, we investigated the postsynaptic distribution of the dopaminergic terminals in the inferior olive at the ultrastructural level. About a third (32%) of the dopaminergic terminals was found to make synaptic contacts in the olivary neuropil. The majority (81%) of these boutons terminated on cell bodies or extraglomerular dendrites, while the remaining terminals contacted dendritic spines inside glomeruli. In contrast, GABAergic terminals in the inferior olive formed more frequently (66%) synaptic contacts and they terminated more frequently (38%) in glomeruli. Thus, the ventrolateral outgrowth receives a dopaminergic input from the mesodiencephalic junction, and the postsynaptic distribution of this input reveals a characteristic pattern.
