Synaptic organization of the human striatum: A postmortem ultrastructural study

Abstract

The goal of this study was to characterize the synaptic organization of the normal human adult striatum for comparison with other species and with the diseased human striatum. Samples of striatal tissue from the Maryland Brain Collection obtained at autopsy with postmortem intervals of less than 4 hours were prepared for electron microscopic analysis according to standard techniques. The caudate nucleus and the putamen were similar in terms of the proportions of synaptic subtypes, the lengths of synaptic subtypes, and the area of most types of axon terminals. The proportions of major striatal synaptic subdivisions, such as axospinous synapses (83.5%) and asymmetric synapses (77.5%), were similar to that of the monkey (82% and 77%, respectively) but slightly lower than found in the rat (90% and 89%, respectively). Interestingly, the proportion of synapses with perforated postsynaptic densities (23%), a type of synapse thought to represent synaptic plasticity, was much higher in humans than in rats (5-8%). The lengths of asymmetric synapses (0.697 micron) were significantly longer than that of symmetric synapses (0.423 microns), a relationship found in other mammals. Also, the areas of terminals forming asymmetric synapses (0.707 micron2) were larger than those forming symmetric synapses (0.401 micron2), also consistent with data from other species. The length of axospinous synapses (0.656 micron) and the area of the terminals forming them (0.611 micron2) were not significantly different from the length of axodendritic synapses (0.523 micron) or the area of terminals forming them (0.602 micron2). This study is the first quantitative study on synaptic organization in human postmortem striatum. The results indicate that the synaptic organization of the human striatum is similar, but not identical, to that of other mammalian species.

Age-Related Changes in the Synapses of the Rat' Neostriatum

“…The light-and electronmicroscopic observations on the neostriatum (Mori, 1966;Tennyson et al, 1972;Bak et al, 1975;Pasik et al, 1976Pasik et al, , 1979Braak & Braak, 1982;Graybiel et al, 1983;Gerfen, 1984Gerfen, , 1985Contant et al, 1996;Hanley & Bolam, 1997;Roberts et al, 1996) are of primary importance, since the basal ganglia are involved in movement control, control of muscle tone, participate in cognitive tasks, and influence mood and motivation (Brodal, 1998). We confirm in the present study, that the most common synapse in the neostriatal neuropil is the ASS.…”

Cholinergic interneurons in the dorsal and ventral striatum: anatomical and functional considerations in normal and diseased conditions

“…6). 82,131,132,[218][219][220][221][222][223][224][225][226] In a recent quantitative study, we demonstrated that 60% of all terminals in contact with ChIs in the monkey postcommissural putamen are GABAergic, while about 20% are putatively glutamatergic (asymmetric synapses/GABA-negative), and the remaining 20% are of unknown chemical phenotype (symmetric synapses/GABA-negative) ( Fig. 5).…”

Neuronal angiogenic effect of sildenafil citrate

“…The corpus striatum is the largest component of the basal ganglia, which is located within the depth of each cerebral hemisphere, and is divided into two parts, the neostriatum (caudate nucleus-putamen) and paleostriatum (globus pallidus) [2]. It plays a role in diverse functions ranging from movement control and cognitive function to regulation of emotional behavior [3].…”