The interactions between predator and prey represent some of the most dramatic events in nature and constitute a matter of life and death for both sides. The hypothalamus has been implicated in driving predation and evasion; however, the exact hypothalamic neural circuits underlying these behaviors remain poorly defined. Here, we demonstrate that inhibitory and excitatory projections from the m...

Introduction The midbrain periaqueductal gray matter (PAG) is involved in a number of key homeostatic neurobiological functions, such as pain modulation and cardiorespiratory control. Currently, most of our understanding of its structure and function comes from animal research, and the translation of these findings to humans has yet to be accomplished non-invasively. Despite its cytoarchitecton...

The role of 5-hydroxytryptamine 1A (5-HT(1A)) receptors located in the rostral ventrolateral medulla (RVLM) in the mediation of a sympathoinhibitory and depressor response elicited from the ventrolateral periaqueductal gray (vlPAG) matter of the midbrain was examined in pentobarbital sodium-anesthetized rats. Activation of neurons in the vlPAG evoked a decrease in renal and lumbar sympathetic n...

Morphine is a well-known mu-opioid receptor (MOR) agonist and an efficient analgesic, but its long-term use inevitably leads to drug addiction and tolerance. Here, we show that specific inhibition of beta-arrestin2 with its siRNA lentivirus microinjected in mice periaqueductal gray matter (PAG) significantly improved both acute and chronic morphine analgesia and delayed the tolerance in the hot...

PURPOSE A T1-weighted multishot inversion-recovery (IR) echo-planar MR imaging (EPI) sequence was developed to improve intracranial tissue differentiation; its diagnostic utility was compared with that of conventional axial T1-weighted spin-echo and axial T2-weighted turbo spin-echo sequences. METHODS Eighteen patients with known or suspected primary or metastatic brain neoplasia were imaged ...

Background: Magnetic resonance imaging (MRI) is currently considered the gold standard in confirming the diagnosis of Wernicke encephalopathy (WE), with classic findings including symmetric involvement of medial thalami, mammillary bodies and periaqueductal gray matter. Case Report: A 58-year-old alcoholic male presented to our hospital with an altered state of consciousness, unsteady gait and ...

behaviors have already been demonstrated. Systemic morphine inhibited both the early and late phases of the formalin-induced licking responses, and this action was naloxone-sensitive (Dubuisson & Dennis, 1977; Oluyomi, Hart, & Smith, 1992) as well. It has been shown that wide variety of brain regions including the frontal lobe, anterior cingulate cortex, insula, amygdala, hypothalamus, periaque...

The aim was to investigate urodynamic parameters and functional excitability of the periaqueductal gray matter (PAG) during changes in sleep-like brain states in urethane anesthetized rats. Simultaneous recordings of detrusor pressure, external urethral sphincter (EUS) electromyogram (EMG), cortical electroencephalogram (EEG), and single-unit activity in the PAG were made during repeated voidin...

BACKGROUND Recent studies have revealed that N2O exerts its antinociceptive effect by inducing opioid peptide release in the brain stem, thereby activating the descending noradrenergic inhibitory neurons, which modulate pain processing in the spinal cord. However, the precise neuronal pathways that mediate these events remain to be determined. METHODS Using immunohistochemical and behavioral ...