Selective degeneration of two out of the nine types of synapses in cat caudate nucleus after cortical lesions

Abstract

In the cat caudate nucleus the same nine types of synapses are found as in putamen and fundus striati. The three parts of the striatum in the strict sense do not differ in the morphological differentiation of synapse types but only in their quantitative distribution. One-third of all synapses in the caudate nucleus are axo-spinous type IV synapses with a curved and divided asymmetric contact. This strongly suggests that the caudate nucleus interneuronal apparatus is dominated by centre-median input, in contrast to the putamen which is controlled by the cortico-striatal input to its internuncial cells and by its strong intrastriatal feedback mechanism. Extensive destruction of the convexity of the cortex and the medial cortex in one hemisphere results in dark degeneration of a large proportion of two of the nine types of caudate synapses: a) the axo-dendritic type VII synapses exciting the large spiny caudate neurons and b) the axo-spinous type III synapses making contact with the small spiny neurons of the interneuronal cell apparatus.

An examination of synaptic proteins following chronic haloperidol in a rat model of tardive dyskinesia.

“…Other studies have compared High and Low VCM rats as far as neuronal spine size and density. In the mammalian striatum the most prevalent neuronal subtype is the medium spiny projection neuron and the majority of striatal synapses are formed with these spines (Chung, Hassler, & Wagner, 1977;Hassler, Chung, Rinne, & Wagner, 1978;Kemp & Powell, 1971a, 1971bRoberts, Gaither, Peretti, Lapidus, & Chute, 1996). Thus, changes in spine size or density could have profound effects on striatal synaptic organization.…”

3-Hydroxyanthranilic acid oxygenase-containing astrocytic processes surround glutamate-containing axon terminals in the rat striatum

“…The distribution of glutamate-i was analyzed using SIGMA-SCAN software to quantify the number of colloidal gold particles per square micron in the following profiles: axon terminals forming asymmetric synapses; axon terminals forming symmetric synapses; astrocytic processes; dendrites and the lumen of capillaries. Axon terminals forming asymmetric synapses were not subdivided according to subtypes of Hassler et al (1978). Gold particle density values do not include mitochondrial labeling.…”

Effect of neonatal administrations of 6-OHDA on the brain development. I. Alteration in the striatum.

“…However, the synaptic sites and the precise structures of dopaminergic nerve endings are still uncertain (KAWANA et al, 1971;IMAMOTO and SHIMIZU, 1977). After interruption of the corticostriatal and thalamostriatal connections, dark degeneration features were recognized in the boutons of axo-dendritic and axo-spinous synapses (KEMP, 1968;KEMP and POWELL, 1970;HASSLER et al, 1978). Due to those data the synaptic sites of the nigro-neostriatal projections may be excluded from the above-mentioned synaptic regions, though ARLUISON and collaborators (1978a, b) neglected the synaptic sites and concluded that dopaminergic endings mainly form asymmetric synapses containing small crowded vesicles.…”