A group of neurokinin-1 receptor-immunoreactive neurons expressing phospho-extracellular signal-regulated protein kinases in the pre-Bötzinger complex of rats

✍ Scribed by Jin-Ping Liu; Ying-Ying Liu; Margaret T.T. Wong-Riley; Hui-Ling Liu; Gong Ju

• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: English
• Weight: 413 KB
• Volume: 80
• Category: Article
• ISSN: 0360-4012
• DOI: 10.1002/jnr.20445

✦ Synopsis

Extracellular-signal-regulated kinases (ERKs) were described originally as critical regulators of cell growth and differentiation. ERKs have received increasing attention as important regulators of neuronal function, especially in synaptic plasticity and memory. We found a group of phospho-ERK1/2 (pERK1/2)-immunoreactive (ir) neurons in the ventrolateral medulla oblongata of adult rats. In the pre-Bo ¨tzinger complex (pre-Bo ¨tC) region, identified by neurokinin-1 receptor (NK1R) immunoreactivity, the distribution of pERK1/2-ir neurons seemed to overlap with that of NK1R-ir neurons. A detailed study combining immunofluorescence and immunogold-silver staining was designed to determine whether ERK-ir neurons were NK1R-ir and related to respiratory function in the pre-Bo ¨tC. The pERK1/2 immunoreactivity was present mainly in somas and processes of small-to medium-sized neurons. Of pERK1/2-ir neurons in the pre-Bo ¨tC, 19.7% were NK1R-ir. Some of the small, fusiform, NK1R-ir neurons, the putative rhythmogenic neurons, were also pERK1/2-ir. Under the electron microscope, immunogold particles indicative of pERK1/2 immunoreactivity were found in somas and dendrites in pre-Bo ¨tC neurons. They were associated mainly with rough endoplasmic reticula and ribosomes. Immunogold particles could also be found in nuclei, but were absent from nucleoli. The existence of pERK1/2 in a subtype of NK1R-ir pre-Bo ¨tC neurons implies that the pERK cascade may play a role in normal respiratory activity in adult rats. The pERK cascade may also participate in sympathoexcitatory activity, given that 42.2% of pERK1/2-ir neurons expressed tyrosine hydroxylase, a marker of C1 adrenergic neurons in the ventrolateral medulla oblongata.