The preoptic area/anterior hypothalamus, a region that contains neurons that control thermoregulation, is the main locus at which histamine affects body temperature. Here we report that histamine reduced the spontaneous firing rate of GABAergic preoptic neurons by activating H3 subtype histamine receptors. This effect involved a decrease in the level of phosphorylation of the extracellular signalregulated kinase and was not dependent on synaptic activity. Furthermore, a population of non-GABAergic neurons was depolarized, and their firing rate was enhanced by histamine acting at H1 subtype receptors. In our experiments, activation of the H1R receptors was linked to the PLC pathway and Ca 2ϩ release from intracellular stores. This depolarization persisted in TTX or when fast synaptic potentials were blocked, indicating that it represents a postsynaptic effect. Single-cell reverse transcription-PCR analysis revealed expression of H3 receptors in a population of GABAergic neurons, while H1 receptors were expressed in non-GABAergic cells. Histamine applied in the median preoptic nucleus induced a robust, long-lasting hyperthermia effect that was mimicked by either H1 or H3 histamine receptor subtype-specific agonists. Our data indicate that histamine modulates the core body temperature by acting at two distinct populations of preoptic neurons that express H1 and H3 receptor subtypes, respectively.

Inflammatory diseases are highly associated with affective disorders including depression and anxiety. While the role of the innate immune system on emotionality has been extensively studied, the role of adaptive immunity is less understood. Considering that chronic inflammatory conditions are mediated largely by maladaptive lymphocyte function, the role of these cells on brain function and behavior during inflammation warrants investigation. In the present study we employed mice deficient in lymphocyte function and studied behavioral and inflammatory responses during challenge with bacterial lipopolysaccharides (LPS). Rag2−/− mice lacking mature lymphocytes were susceptible to death under sub-septic (5 mg/kg) doses of LPS and survived only to moderate (1 mg/kg) doses of LPS. Under these conditions, they displayed attenuated TNF-alpha responses and behavioral symptoms of sickness when compared with immunocompetent mice. Nevertheless, Rag2−/− mice had protracted motivational impairments after recovery from sickness suggesting a specific function for lymphocytes on the reestablishment of motivational states after activation of the innate immune system. The behavioral impairments in Rag2−/− mice were paralleled by an elevation in plasma corticosterone after behavioral tests. These results provide evidence that the absence of adaptive immunity may be associated with emotional deficits during inflammation and suggest that depressive states associated with medical illness may be mediated in part by impaired lymphocyte responses.

Purpose of review Antenatal anesthesia clinics remain uncommon despite the rising incidence of maternal morbidity and mortality in the United States. The purpose of the present review is to outline the major considerations and challenges surrounding antenatal anesthetic evaluation. Recent findings Data from the general surgical population would suggest a mortality benefit associated with preoperative anesthesia evaluation, although no such data exists in the obstetric population. Robust systems for case ascertainment and referral are needed. Recent publications on obstetric comorbidity indices may provide useful tools to ascertain high-risk parturients for a referral to antenatal obstetric anesthesiology clinics and higher levels of maternal care. Major obstetric organizations have identified and laid out criteria for maternal level of care. Anesthesiology resources also play a role in these designations and can help triage patients to facilities with appropriate resources. Summary Obstetric anesthesiologists have a critical role not only in preoperative patient optimization but also in coordinating multidisciplinary care for optimal patient outcomes.

3. Jacobsen SJ, Goldberg J, Miles TP, Brody JA, Stiers W, Rimm AA. Hip fracture incidence among the old and very old: a population-based study of 745,435 cases. American Journal of Public Health. 1990;80 (7)