To the Editor:—I read with interest the reports by Yaksh et al. and Gradert et al. in the July 2003 issue of ANESTHESIOLOGY describing the association of intrathecal analgesia with catheter-associated masses and the accompanying editorial by Follett. Both articles describe a clear doseand/or concentration-dependent relation between commercially prepared preservative-free morphine sulfate and th...

[Dmt(1)]DALDA (H-Dmt-d-Arg-Phe-Lys-NH(2); Dmt = 2',6'-dimethyltyrosine) is a dermorphin analog that shows high affinity and selectivity for the mu opioid receptor. The intrathecal potency of [Dmt(1)]DALDA far exceeded its affinity at mu receptors and suggests that other mechanisms must be involved in its action in the spinal cord. The affinity and selectivity of [Dmt(1)]DALDA was determined usi...

Central opioid receptor activation triggers cardioprotection against ischemia reperfusion injury, independent of peripheral opioid receptor activity. Using a rodent model of myocardial ischemia reperfusion injury with infarct size as the primary outcome, we tested the hypothesis that spinal opioids confer this beneficial effect via a neural pathway. Intrathecal morphine reduced the infarct size...

The possible characteristics of spinal interaction between sildenafil (phosphodiesterase 5 inhibitor) and morphine on formalin-induced nociception in rats was examined. Then the role of the opioid receptor in the effect of sildenafil was further investigated. Catheters were inserted into the intrathecal space of male Sprague-Dawley rats. For induction of pain, 50 microL of 5% formalin solution ...

Agonists acting at alpha2 adrenergic and opioid receptors have analgesic properties and act synergistically when co-administered in the spinal cord; this synergy may also contribute to the potency and efficacy of spinally administered morphine. The lack of subtype-selective pharmacological agents has previously impeded the definition of the adrenergic receptor subtype(s) mediating these effects...

The endogenous opioid dynorphin A-(1-17) (Dyn A) has been implicated as a mediator of tissue damage after traumatic spinal cord injury (TSCI) and causes hindlimb paralysis when administered intrathecally. Motor impairment following intrathecal Dyn A is attenuated by antagonists of excitatory amino acids (EAAs); whether opioid receptors mediate such injury has been questioned. TSCI causes variou...

A lanthionine enkephalin derivative, Tyr-c[D-ValL-Gly-Phe-DAlaL ]-OH (DVL DAL LanEnk), where ValL and AlaL denote the lanthionine amino acid ends linked via a monosulfide bridge to form the lanthionine structure, was synthesized. It was found to possess selectivity for and potency at the versus opioid receptor as defined by binding studies and by its respective activity on the mouse vas deferen...

DALDA (H-Tyr-D-Arg-Phe-Lys-NH2) and [Dmt ]DALDA (H-DmtD-Arg-Phe-Lys-NH2) (Dmt 5 29,69-dimethyltyrosine) are potent and highly selective m-opioid agonists (Ki d/Ki m . 10,000 and Ki k/Ki m . 100). Both peptides carry a 31 charge at physiological pH. Their antinociceptive and respiratory effects were compared with morphine (MOR) after intrathecal administration in rats. Both DALDA and [Dmt]DALDA ...

To enhance analgesia, the combinatorial use of analgesic drugs with proven efficacies is a widely-used strategy to reduce adverse side effects. The present study characterizes the antinociceptive interaction of intrathecal morphine co-administered with different NSAIDs using isobolographic analysis.Antinoceptive activity was evaluated using a model for acute visceral pain, the writhing test of ...

UNLABELLED Methadone is a synthetic opioid analgesic that is used as an alternate to morphine and hydromorphone for patients with severe pain. It is increasingly being used in opioid rotation schedules. Methadone has an asymmetric carbon atom resulting in 2 enantiomeric forms, the d and l isomers. The racemic mixture (dl-methadone) is the form commonly used clinically. Recent studies have revea...