introduction: orexin-a and b (hypocretin 1 and 2) are neuropeptides that are mostly expressed in the posterior and lateral hypothalamus (lh). intracisternal (icv) and intratechal (it) injections of orexin-a (hypocretin-1) have been shown to elicit analgesic responses in formalin test. however, the locations of central sites that may mediate these effects have not been clearly elucidated. orexin...

Brainstem strokes affecting the periaqueductal gray matter of the midbrain can cause vertical ophthalmoplegia. Accompanying clinical features are frequently associated and reflect the involvement of other brainstem structures. We report on an adolescent presenting with vertical gaze palsy and left mydriatic pupil as the only clinical expression of a small infarct located in the left periaqueduc...

objective(s): as heat, pain is one of the most common clinical symptoms. generally, calcitonin (ct) is prescribed as an analgesic agent for the treatment of pain, especially for the pain caused by osteoporosis or primary and metastatic bone tumor. however, the detailed mechanism remains unknown.materials and methods: in this study, chronic constriction injury (cci) rat model was created, and ho...

Previous work showed that the dorsal periaqueductal gray is involved in the inhibition of fear-potentiated startle. The present study investigated the effects of blockade and stimulation of Kainate/AMPA and GABA(A) receptors within the dorsal periaqueductal gray on expression and conditioned inhibition of fear-potentiated startle. Blockade of the Kainate/AMPA receptors enhanced whereas stimulat...

Patients with chronic daily headache and overuse of analgesics, triptans, or other acute headache compounds, are considered to suffer from medication-overuse headache (MOH). This implies that medication overuse is the cause of headache chronification. It remains a key question why only two-thirds of patients with chronic migraine-like headache and overuse of pain medication improve after detoxi...

Single unit activity was recorded extracellularly from the periaqueductal gray matter (PAG) and the superior colliculus of three monkeys during spontaneous saccades and fixation. Most saccade-related cells were found in the dorsal and lateral regions of the PAG and they paused with saccades. The pause preceded the onset of saccades by 34.5 +/- 6.8 msec (n = 31). In 90% of the 31 PAG cells, the ...

BACKGROUND AND PURPOSE Subclinical cerebral edema occurs in many, if not most, children with diabetic ketoacidosis (DKA) and may be an indicator of subtle brain injury. Brain ratios of N-acetylaspartate (NAA) to creatine (Cr), measured by proton MR spectroscopy, decrease with neuronal injury or dysfunction. We hypothesized that brain NAA/Cr ratios may be decreased in children in DKA, indicating...