%0 Journal Article %T Lamina I NK1 expressing projection neurones are functional in early postnatal rats and contribute to the setting up of adult mechanical sensory thresholds %A Sharon HW Man %A Sandrine M Geranton %A Stephen P Hunt %J Molecular Pain %D 2012 %I BioMed Central %R 10.1186/1744-8069-8-35 %X At P3, a subset of lamina I neurons were found to express the neurokinin 1 (NK1) receptor. Using fluorogold retrograde tracing, we found that the NK1 positive neurons projected upon the parabrachial nucleus (PB) within the hindbrain. Using c-fos immunohistochemistry, we showed that lamina I and PB neurons in P3 rats responded to noxious stimulation of the periphery. Finally, ablation of lamina I neurons with substance-P saporin conjugates at P3 resulted in increased mechanical sensitivity from P45 onwards compared to control animals of the same age.These results suggest that the lamina I pathway is present and functional at least from P3 and required for establishing and fine-tuning mechanical sensitivity in adult rats. %K Lamina 1 %K Projection neurones %K Parabrachial nucleus %K c-fos %K NK1 %K Formalin %K Postnatal rat %K Substance-P saporin %K Mechanical sensory thresholds %U http://www.molecularpain.com/content/8/1/35/abstract