Biomaterial Database

Spinal mu-opioid receptor-expressing dorsal horn neurons: role in nociception and morphine antinociception. 2008

Robert H Kline, and Ronald G Wiley

Laboratory of Experimental Neurology, Tennessee Valley Healthcare System, Nashville, Tennessee 37212-2637, USA.

The role of spinal cord mu-opioid receptor (MOR)-expressing dorsal horn neurons in nociception and morphine analgesia is incompletely understood. Using intrathecal dermorphin-saporin (Derm-sap) to selectively destroy MOR-expressing dorsal horn neurons, we sought to determine the role of these neurons in (1) normal baseline reflex nocifensive responses to noxious thermal stimulation (hotplate, tail flick) and to persistent noxious chemical stimulation (formalin) and (2) the antinociceptive activity of intrathecal and systemic morphine in the same tests. Lumbar intrathecal Derm-sap (500 ng) produced (1) partial loss of lamina II MOR-expressing dorsal horn neurons, (2) no effect on MOR-expressing dorsal root ganglion neurons, and (3) no change in baseline tail-flick and hotplate reflex nocifensive responses. Derm-sap treatment attenuated the antinociceptive action of both intrathecal and systemic morphine on hotplate responses. Derm-sap treatment had two effects in the formalin test: (1) increased baseline nocifensive responding and (2) reduced antinociceptive action of systemic morphine. We conclude that MOR-expressing dorsal horn neurons (1) are not essential for determining nocifensive reflex responsiveness to noxious thermal stimuli, (2) are necessary for full antinociceptive action of morphine (intrathecal or systemic) in these tests, and (3) play a significant role in the endogenous modulation of reflex nocifensive responses to persistent pain in the formalin test. Thus, one would predict that altering the activity of MOR-expressing dorsal horn neurons would be antinociceptive and of interest in the search for new approaches to management of chronic pain.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D009020	Morphine	The principal alkaloid in opium and the prototype opiate analgesic and narcotic. Morphine has widespread effects in the central nervous system and on smooth muscle.	Morphine Sulfate,Duramorph,MS Contin,Morphia,Morphine Chloride,Morphine Sulfate (2:1), Anhydrous,Morphine Sulfate (2:1), Pentahydrate,Oramorph SR,SDZ 202-250,SDZ202-250,Chloride, Morphine,Contin, MS,SDZ 202 250,SDZ 202250,SDZ202 250,SDZ202250,Sulfate, Morphine
D010146	Pain	An unpleasant sensation induced by noxious stimuli which are detected by NERVE ENDINGS of NOCICEPTIVE NEURONS.	Suffering, Physical,Ache,Pain, Burning,Pain, Crushing,Pain, Migratory,Pain, Radiating,Pain, Splitting,Aches,Burning Pain,Burning Pains,Crushing Pain,Crushing Pains,Migratory Pain,Migratory Pains,Pains, Burning,Pains, Crushing,Pains, Migratory,Pains, Radiating,Pains, Splitting,Physical Suffering,Physical Sufferings,Radiating Pain,Radiating Pains,Splitting Pain,Splitting Pains,Sufferings, Physical
D010147	Pain Measurement	Scales, questionnaires, tests, and other methods used to assess pain severity and duration in patients or experimental animals to aid in diagnosis, therapy, and physiological studies.	Analgesia Tests,Analogue Pain Scale,Formalin Test,McGill Pain Questionnaire,Nociception Tests,Pain Assessment,Pain Intensity,Pain Severity,Tourniquet Pain Test,Visual Analogue Pain Scale,Analog Pain Scale,Assessment, Pain,McGill Pain Scale,Visual Analog Pain Scale,Analgesia Test,Analog Pain Scales,Analogue Pain Scales,Formalin Tests,Intensity, Pain,Measurement, Pain,Nociception Test,Pain Assessments,Pain Intensities,Pain Measurements,Pain Questionnaire, McGill,Pain Scale, Analog,Pain Scale, Analogue,Pain Scale, McGill,Pain Severities,Pain Test, Tourniquet,Questionnaire, McGill Pain,Scale, Analog Pain,Scale, Analogue Pain,Scale, McGill Pain,Severity, Pain,Test, Analgesia,Test, Formalin,Test, Nociception,Test, Tourniquet Pain,Tests, Nociception,Tourniquet Pain Tests
D005260	Female		Females
D005786	Gene Expression Regulation	Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control (induction or repression) of gene action at the level of transcription or translation.	Gene Action Regulation,Regulation of Gene Expression,Expression Regulation, Gene,Regulation, Gene Action,Regulation, Gene Expression
D000700	Analgesics	Compounds capable of relieving pain without the loss of CONSCIOUSNESS.	Analgesic,Anodynes,Antinociceptive Agents,Analgesic Agents,Analgesic Drugs,Agents, Analgesic,Agents, Antinociceptive,Drugs, Analgesic
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D017207	Rats, Sprague-Dawley	A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.	Holtzman Rat,Rats, Holtzman,Sprague-Dawley Rat,Rats, Sprague Dawley,Holtzman Rats,Rat, Holtzman,Rat, Sprague-Dawley,Sprague Dawley Rat,Sprague Dawley Rats,Sprague-Dawley Rats
D017450	Receptors, Opioid, mu	A class of opioid receptors recognized by its pharmacological profile. Mu opioid receptors bind, in decreasing order of affinity, endorphins, dynorphins, met-enkephalin, and leu-enkephalin. They have also been shown to be molecular receptors for morphine.	Morphine Receptors,Opioid Receptors, mu,Receptors, Morphine,Receptors, mu,Receptors, mu Opioid,mu Receptors,Morphine Receptor,mu Opioid Receptor,mu Receptor,Opioid Receptor, mu,Receptor, Morphine,Receptor, mu,Receptor, mu Opioid,mu Opioid Receptors