Trending Articles
-
Mounting evidence from both humans and rodents suggests that tissue damage during the neonatal period can "prime" developing nociceptive pathways such that a subsequent injury during adulthood causes an exacerbated degree of pain hypersensitivity. However, the cellular and molecular mechanisms that underlie this priming effect remain poorly understood. Here, we demonstrate that neonatal surgical injury relaxes the timing rules governing long-term potentiation (LTP) at mouse primary afferent synapses onto mature lamina I projection neurons, which serve as a major output of the spinal nociceptive network and are essential for pain perception. In addition, whereas LTP in naive mice was only observed if the presynaptic input preceded postsynaptic firing, early tissue injury removed this temporal requirement and LTP was observed regardless of the order in which the inputs were activated. Neonatal tissue damage also reduced the dependence of spike-timing-dependent LTP on NMDAR activation and unmasked a novel contribution of Ca(2+)-permeable AMPARs. These results suggest for the first time that transient tissue damage during early life creates a more permissive environment for the production of LTP within adult spinal nociceptive circuits. This persistent metaplasticity may promote the excessive amplification of ascending nociceptive transmission to the mature brain and thereby facilitate the generation of chronic pain after injury, thus representing a novel potential mechanism by which early trauma can prime adult pain pathways in the CNS. ⋯ Tissue damage during early life can "prime" developing nociceptive pathways in the CNS, leading to greater pain severity after repeat injury via mechanisms that remain poorly understood. Here, we demonstrate that neonatal surgical injury widens the timing window during which correlated presynaptic and postsynaptic activity can evoke long-term potentiation (LTP) at sensory synapses onto adult lamina I projection neurons, which serve as a major output of the spinal nociceptive circuit and are essential for pain perception. This persistent increase in the likelihood of LTP induction after neonatal injury is predicted to favor the excessive amplification of ascending nociceptive transmission to the mature brain in response to subsequent injury and thereby exacerbate chronic pain.
-
The embryonic ventricular and subventricular zones (VZ/SVZ) contain the neuronal stem and progenitor cells and undergo rapid proliferation. The intermediate zone (IZ) contains nonreplicating, differentiated cells. The VZ/SVZ is hypersensitive to radiation-induced apoptosis. ⋯ We demonstrate a functional G(2)/M checkpoint in VZ/SVZ cells and show that it is not activated by low numbers of DSBs, allowing damaged VZ/SVZ cells to transit into the IZ. We propose a novel model in which microcephaly in LIG4 syndrome arises from sensitive apoptotic induction from persisting DSBs in the IZ, which arise from high endogenous breakage in the VZ/SVZ and transit of damaged cells to the IZ. The VZ/SVZ, in contrast, is highly sensitive to acute radiation-induced DSB formation.
-
Dementia is a progressive life limiting condition with increasing prevalence and complex needs. Palliative care needs of patients with dementia are often poorly addressed; symptoms such as pain are under treated while these patients are over subjected to burdensome interventions. Research into palliative care in dementia remains limited but recent developments together with national guidelines and policies set foundations for improving the delivery of palliative care to this group of the population.