Rearrangement of the dendritic morphology of the neurons from prefrontal cortex and hippocampus after subthalamic lesion in Sprague–Dawley rats

Abstract

Several studies in rodents have suggested the inactivation of the subthalamic nucleus (STN) as an alternative strategy to Parkinson's disease (PD) treatment. The STN is part of the basal ganglia and plays an important role in the motor function; however, recent data suggest that this structure has a critical role in the cognitive function of the limbic system. The STN receives direct projection from the prefrontal cortex (PFC), structure interconnected with the hippocampus and both structures send excitatory projections to the nucleus accumbens (NAcc). Here, we determined whether and which changes occurred 4 weeks after a STN lesion in the dendritic morphology of pyramidal neurons of the layers 3 and 5 of the PFC and basolateral amygdala, neurons of the ventral hippocampus, and the medium spiny neurons of the NAcc and caudate-putamen. Dendritic morphology was measured using the Golgi-Cox procedure followed by Sholl analysis. We also evaluated the effects of STN lesion on locomotor behavior assessed by an open field test, social interaction, acoustic startle response, prepulse inhibition, and locomotor activity induced by a novel environment and amphetamine. We found that STN damage induced a deficit in locomotion measured by open field test with neuronal hypertrophy in PFC (layer 5) and reduced spinogenesis in CA1 ventral hippocampus and PFC (layer 3). Taken together, these data suggest that the behavioral and morphological effects of STN lesion are, at least partially, mediated by limbic subregions with possible consequences for cognitive-related behaviors observed in PD treatment.

Pregnancy improves cognitive deficit and neuronal morphology atrophy in the prefrontal cortex and hippocampus of aging spontaneously hypertensive rats

“…In the present report, a total of 1,600 neurons (400 CA1 hippocampus, 400 DG, and 800 PFC) from SH old rats were assessed for the morphological analysis. By using Golgi‐Cox staining method, dendritic arborization and spines were observed as previously reported (Camacho‐Abrego et al, ; Flores et al, 2005; Juárez‐Méndez et al, ; Vazquez‐Roque et al, ). Representative photomicrograph showing Golgi‐Cox‐impregnated neurons and drawings of neurons from CA1 of the DH, the DG, and the PFC are shown in Figure .…”

Cerebrolysin improves memory and ameliorates neuronal atrophy in spontaneously hypertensive, aged rats

“…The brains were first stored in the dark for 14 days in Golgi‐Cox solution followed by 3 days in 30% sucrose. They were sectioned at 200‐µm thickness at the coronal plane at the level of the dorsal hippocampus (plates 27–32; Bringas et al, ; Camacho‐Abrego et al, ; Flores et al, ; Juárez et al, ; Martinez‐Tellez et al, ; Paxinos and Watson, ) using a vibratome (Camden Instrument, MA752, Leicester, England). Sections were collected on cleaned, gelatin‐coated microscope slides (4 sections/slide) and stained with ammonium hydroxide for 30 min, followed by Kodak Fix for film for another 30 min, and then were washed with water, dehydrated, cleared, and mounted using a resinous medium.…”

The Subthalamic Nucleus, Limbic Function, and Impulse Control

“…One provocative electrophysiological study in rats demonstrated that a very high percentage of neurons in the ventral pallidum (VP), a major limbic output region, changed firing patterns in response to stimulation of the STN (Turner et al ., 2001). Another study in rats suggested that STN lesions associated with changes in cognitive-related behaviors induced neuronal dendritic rearrangement in the prefrontal cortex and hippocampal neurons (Camacho-Abrego et al ., 2014). STN DBS in rats was shown to modulate neurotransmission in limbic brain regions, and specifically spur an increase in dopamine (DA) in the nucleus accumbens (NAc) and a decrease in γ-aminobutyric acid (GABA) in the ventral tegmental area (VTA) (Winter et al ., 2008).…”