Fig 1.
Representative images of DiI-labeled neuron and dendritic segment.
(A) Low power magnification of a DiI-labeled medium spiny neuron, scale bar 50 μm. (B) High power magnification of a reconstructed dendritic segment from a medium spiny neuron, scale bar 5 μm.
Fig 2.
Positive modulation of mGluR5 decreases spine density in the nucleus accumbens but not in the dorsal striatum.
(A) Twenty-four hours after systemic administration, CDPPB (5–10 mg/kg, n = 18 animals) decreased dendritic spine density and frequency of small head diameter spines (0.2 μm bin) compared to vehicle control (n = 8) in the nucleus accumbens core. CDPPB had no effect on neck length. (B) Similarly, CDPPB decreased spine density and frequency of small head diameter spines (0.2 μm bin) in the nucleus accumbens shell, but did not affect neck length. *p < 0.05.
Fig 3.
Positive modulation of mGluR1a increases spine density in the nucleus accumbens but not in the dorsal striatum.
(A) Twenty-four hours after systemic administration, SYN119 (10 mg/kg, n = 10 animals) increased dendritic spine density compared to vehicle control (n = 9) in the nucleus accumbens core but had no effect on spine length or head diameter. (B) SYN119 also decreased spine density in the nucleus accumbens shell and did not affect spine length or head diameter. *p < 0.05.
Fig 4.
Activation of mGluR5 site-specifically decreases spine density in the nucleus accumbens.
(A) Schematic representation of injection sites of either vehicle (open circles) or CHPG (filled circles). Numbers represent distance from bregma, based on the atlas of Paxinos and Watson [16]. (B)Twenty-four hours after local microinfusion to the nucleus accumbens, CHPG (10 μg/side, n = 7 animals) decreased dendritic spine density compared to vehicle control (n = 7) in the nucleus accumbens core but had no effect on spine length or head diameter. (B) CHPG also decreased spine density in the nucleus accumbens shell and did not affect spine length or head diameter. *p < 0.05.