Figure 11.

Ultrastructural interactions among microglia, astrocytes and neurons in the AVCN are regulated by noise (n = 4 for each group). In response to noise-exposure, reactive microglial processes came into close proximity with astrocytes, terminals, and synapse-associated elements at all time points evaluated (A,B). Note that the perivascular microglial cell in (B,B1) is in close contact with an astrocyte (large asterisk) and is wrapping around a dendrite making synapses with multiple terminals (small asterisks). Although interactions among microglia, astrocytes and neuronal elements were observed at all time points post-exposure (A–A3), they increased in frequency particularly on day 30 (B,B1). Appositions between microglia and astrocytes are indicated by large asterisks while the small asterisks in (B1) point to synapses. Higher magnification images of (A,B) are represented in (A1–A3, B1); respectively. As, astrocyte; Ax, axon; D1–D3, dendrites; Mg, microglia, P1–P2, microglial processes; T1–T3, terminals. Scale bars: 5 μm in (A, B1); 2.5 μm in (A3; it also applies to A1,A2); 2 μm in (B).