Chronic pain-induced neuronal plasticity in the bed nucleus of the stria terminalis causes maladaptive anxiety.

The comorbidity of chronic pain and mental dysfunctions such as depression and anxiety disorders has long been recognized, but the underlying mechanisms remain poorly understood. Here, using a mouse model of neuropathic pain, we demonstrated neuronal plasticity in the bed nucleus of the stria terminalis (BNST), which plays a critical role in chronic pain-induced maladaptive anxiety. Electrophysiology demonstrated that chronic pain increased inhibitory inputs to lateral hypothalamus (LH)-projecting BNST neurons. Chemogenetic manipulation revealed that sustained suppression of LH-projecting BNST neurons played a crucial role in chronic pain-induced anxiety. Furthermore, using a molecular genetic approach, we demonstrated that chronic pain elevated the excitability of a specific subpopulation of BNST neurons, which express cocaine- and amphetamine-regulated transcript (CART). The elevated excitability of CART-positive neurons caused the increased inhibitory inputs to LH-projecting BNST neurons, thereby inducing anxiety-like behavior. These findings shed light on how chronic pain induces psychiatric disorders, characterized by maladaptive anxiety.

Amygdalohippocampal Area Neurons That Project to the Preoptic Area Mediate Infant-Directed Attack in Male Mice.

Male animals may show alternative behaviors toward infants: attack or parenting. These behaviors are triggered by pup stimuli under the influence of the internal state, including the hormonal environment and/or social experiences. Converging data suggest that the medial preoptic area (MPOA) contributes to the behavioral selection toward the pup. However, the neural mechanisms underlying how integrated stimuli affect the MPOA-dependent behavioral selection remain unclear. Here we focus on the amygdalohippocampal area (AHi) that projects to MPOA and expresses oxytocin receptor, a hormone receptor mediating social behavior toward pups. We describe the activation of MPOA-projection AHi neurons in male mice by social contact with pups. Input mapping using the TRIO method reveals that MPOA-projection AHi neurons receive prominent inputs from several regions, including the thalamus, hypothalamus, and olfactory cortex. Electrophysiological and histologic analysis demonstrates that oxytocin modulates inhibitory synaptic responses on MPOA-projection AHi neurons. In addition, AHi forms the excitatory monosynapse to MPOA, and pharmacological activation of MPOA-projection AHi neurons enhances only aggressive behavior, but not parental behavior. Interestingly, this promoted behavior was related to social experience in male mice. Collectively, our results identified a presynaptic partner of MPOA that can integrate sensory input and hormonal state, and trigger pup-directed aggression.SIGNIFICANCE STATEMENT The medial preoptic area (MPOA) plays critical roles in parental behavior, such as motor control, motivation, and social interaction. The MPOA projects to multiple brain regions, and these projections contribute to several neural controls in parental behavior. In contrast, how inputs to MPOA are regulated by social and environmental information is poorly understood. In this study, we focus on the amygdalohippocampal area (AHi) that connects to MPOA and expresses oxytocin receptor. We demonstrate the disruption of the expression of parental behavior triggered by the activation of MPOA-projection AHi neurons. This behavior may be regulated not only by oxytocin but also by neural input from several regions.

Evaluation of Measures against Exposure during Administration of Hazardous Drugs through a Feeding Tube.

Hazardous drugs (HD), which need to be handled with care, may be administered through a feeding tube using the simple suspension method. However, instrument contamination during HD administration with the simple suspension method remains unclear. Therefore, to minimize such contamination during the simple suspension method using an injector, we propose the following exposure countermeasures method: (1) Wear two layers of gloves. (2) Prepare injectors for administration and flushing. (3) Use caps. (4) Replace outer gloves after the removal of tablets from the press-through package (PTP) sheet. (5) Handle drugs on a tray. (6) Inject while wrapping the connection site between the injector for administration and the tube with gauze. (7) Wrap the connection site between the injector and tube with gauze. (8) Do not point the injector downward. To establish whether these countermeasures method are effective, 16 ward nurses who routinely administer drugs via a feeding tube were enrolled as subjects. By visual evaluation, we compared differences in instrument contamination between a suspension using a medicine cup and administration via a feeding tube (the conventional method) and the exposure countermeasures method. Exposure with the countermeasures method under our instruction was markedly lower than that with the conventional method. Furthermore, after implementing the exposure countermeasures method, most nurses noted that caution and awareness of exposure countermeasures increased. Thus, to minimize exposure, we recommend the implementation of the exposure countermeasures method and increasing knowledge and awareness of measures against exposure.