The Yin and Yang of pain: variability in formalin test nociception and morphine analgesia produced by the Yin Yang 1 transcription factor gene.

We recently observed a reliable phenotypic difference in the inflammatory pain sensitivity of a congenic mouse strain compared to its background strain. By constructing and testing subcongenic strains combined with gene-expression assays, we provide evidence for the candidacy of the Yy1 gene - encoding the ubiquitously expressed and multifunctional Yin Yang 1 transcription factor - as responsible. To confirm this hypothesis, we used a Cre/lox strategy to produce mutant mice in which Yy1 expression was ablated in Nav 1.8-positive neurons of the dorsal root ganglion. These mutants also displayed reduced inflammatory pain sensitivity on the formalin test. Further testing of pain-related phenotypes in these mutants revealed robustly increased sensitivity to systemic and spinal (but not supraspinal) morphine analgesia, and greatly increased endogenous (swim stress-induced) opioid analgesia. None of the known biological roles of Yin Yang 1 were suggestive of such a phenotype, and thus a novel player in pain modulatory systems has been identified.

Transient leucopenia, thrombocytopenia and anaemia associated with severe acute phenobarbital intoxication in a dog.

A nine-year-old Labrador retriever dog was admitted to the emergency unit of the Hebrew University Veterinary Teaching Hospital with acute-onset tremors and coma. It had recently ingested a large quantity of phenobarbital and had a high serum phenobarbital concentration. On this basis, a diagnosis of acute phenobarbital intoxication was made. Significant leucopenia, thrombocytopenia and mild anaemia developed on the third day after admission. The leucopenia resolved on day 6 and the thrombocytopenia on day 13. The red blood cell count remained low for the next month. The dog was discharged on day 13 at which time it was ambulatory but weak. It was completely recovered clinically eight days later. In summary, high levels of serum phenobarbital as a result of acute intoxication induced pancytopenia, which improved when the serum phenobarbital level was normalised.

Effective expression of the green fluorescent fusion proteins in cultured Aplysia neurons.

The green fluorescent fusion protein and its isoforms are extensively used to monitor gene expression, protein localisation and their dynamics in relations to fundamental cellular processes. However, it has not yet been effectively applied to Aplysia neurons that serve as a powerful model to study the mechanisms underlying neuroplasticity. We report here the development of a procedure combining in vitro transcription of mRNA encoding fluorescent-tagged proteins and its subsequent injection into the cytoplasm to image, in real-time, protein dynamics in cultured Aplysia neurones. To illustrate the efficiency of the procedure we report here the visualisation of actin, microtubules and vesicle trafficking. The results presented here introduce a reliable and effective method to express green fluorescent protein (GFP) fusion proteins in cultured Aplysia neurons.