Cholinergic circuitry and muscarinic receptors within the spinal cord have been proposed to contribute to the analgesic effects of systemic morphine. In this study, we determined whether the descending pathways are involved in the inhibitory effect of systemic morphine on dorsal horn projection neurons mediated by activation of the spinal cholinergic system. Single-unit activity of dorsal horn ...

Although chronic pain affects all age ranges, it is particularly common in the elderly. One potential explanation for the high prevalence of chronic pain in the older population is impaired functioning of the descending pain inhibitory system which can be studied in humans using conditioned pain modulation (CPM) paradigms. In this study we investigated (i) the influence of age on CPM and (ii) t...

In the present study, we investigated whether restoring descending noradrenergic inhibitory tone can attenuate pain in a PD rat model, which was established by stereotaxic infusion of 6-hydroxydopamine (6-OHDA) into the bilateral striatum (CPu). PD rats developed thermal and mechanical hypersensitivity at the 4th week after surgery. HPLC analysis showed that NE content, but not dopamine or 5-HT...

Despite nearing the end of the decade of pain research, the analgesic mechanisms of one of the most widely used and popular analgesics remains uncertain. Acetaminophen (APAP) (paracetamol [PARA]) has been used clinically for over a half of a century and although clinicians seem to be comfortable with its benefits, risks, and limitations, they still remain in the dark as to precisely what is pro...

oral ph sensitive drug delivery systems are of utmost importance as these systems deliver the drug at specific part of the gastrointestine (gi) as per the ph of gi, resulting in improved patient therapeutic efficacy and compliance. the ph range of fluids in various segments of the gi tract may provide environmental stimuli for drug release. the aim of this study was to design buoyant beads cont...

OBJECTIVE Chronic pain is believed to be related to a dysfunction of descending pain modulatory mechanisms. Functioning of descending pain modulation can be assessed by various methods, including conditioned pain modulation (CPM). CPM refers to the inhibition of one source of pain by a second noxious stimulus, termed the conditioning stimulus. This procedure can activate an endogenous pain inhi...

A two-compartment, flat-sheet preparation of rat colon was devised, which enabled exclusive measurement of longitudinal muscle activity during the ascending and descending phases of the peristaltic reflex. A previous study using longitudinal muscle strips revealed the operation of an integrated neuronal circuit consisting of somatostatin, opioid, and VIP/pituitary adenylate cyclase-activating p...

In the extrinsically denervated smooth muscle esophagus of the hen anesthetized with urethane (1 g/kg, i. m.), it was studied whether peptidergic neurons in the intramural plexus are involved in the intrinsic reflex. Ascending and descending contractions, and descending relaxation were induced by electrical stimulation of a narrow segment of the esophagus. Naloxone (1 microM), desensitization t...

Tricyclic antidepressants and serotonin noradrenaline reuptake inhibitors are used to treat chronic pain, such as neuropathic pain. Why antidepressants are effective for treatment of neuropathic pain and the precise mechanisms underlying their effects, however, remain unclear. The inhibitory effects of these antidepressants for neuropathic pain manifest more quickly than their antidepressive ef...