Paeoniflorin (PF, C23H28O11), one of the principal active ingredients of Paeonia Radix, exerts depressant effects on the central nervous system. We determined whether PF could modulate sleep behaviors and the mechanisms involved. Electroencephalogram and electromyogram recordings in mice showed that intraperitoneal PF administered at a dose of 25 or 50 mg/kg significantly shortened the sleep la...

Since ancient times ursodeoxycholic acid (UDCA), a constituent of bile, is used against gallstone formation and cholestasis. A neuroprotective action of UDCA was demonstrated recently in models of Alzheimer's disease and retinal degeneration. The mechanisms of UDCA action in the nervous system are poorly understood. We show now that UDCA promotes wakefulness during the active period of the day,...

This study investigated the effects of bilateral intraamygdalar microinjections of PNU-282987, a nicotinic cholinergic agonist, on anxiety and the reversal of amnesia induced by chlorpheniramine (CPA), an H1 histaminergic antagonist, in mice subjected to the elevated plusmaze (EPM). Two experiments were performed with seventy-nine adult male Swiss mice. The isolated microinjections of PNU-28298...

Stress induced analgesia (SIA) is well known, but the reverse phenomenon, hyperalgesia is poorly documented. This study investigated the role of the histaminergic system in restraint stress hyperalgesia in rats, using thermal stimulation method (hot plate and tail flick tests). Paw licking and tail withdrawal latencies were taken before and after restraint for about one hour. Significant decrea...

Brain histamine may affect a variety of different behavioral and physiological functions; however, its role in promoting wakefulness has overshadowed its other important functions. Here, we review evidence indicating that brain histamine plays a central role in motivation and emphasize its differential involvement in the appetitive and consummatory phases of motivated behaviors. We discuss the ...

Consolidation of associative memories appears to require extracellular signal-related kinase2 (ERK2) activation, which is modulated by several factors, including neurotransmitter receptor stimulation. Here we show that in vitro stimulation of either H2 or H3 histaminergic receptors activates ERK2 in hippocampal CA3 pyramidal cells. In behaving animals, bilateral posttraining injections into the...

Involvement of Histaminergic Inputs in the Jaw-Closing Reflex Arc 1 2 Chikako Gemba,* Kiyomi Nakayama,* Shiro Nakamura, Ayako Mochizuki, Mitsuko 3 Inoue, Tomio Inoue 4 5 Department of Oral Physiology, Showa University School of Dentistry, Shinagawa-ku, Tokyo, 6 Japan; and Department of Pediatric Dentistry, Showa University School of Dentistry, 7 Oota-ku, Tokyo, Japan 8 9 Running head: HISTAMINE...

In a recent study, we examined the glycemic and autonomic nervous responses to probiotic strain Lactobacillus johnsonii La1, and presented evidence that intraduodenal (ID) injection of this bacteria affected autonomic nerves and lowered blood pressure (BP) in anesthetized rats. In the study presented here, we examined the feeding, autonomic and cardiovascular effects of the lactobacillus strain...