Biomaterial Database

Development of tolerance to the analgesic effect of clonidine in rats. Cross-tolerance to morphine. 1978

G Paalzow

The influence of chronic treatment with clonidine on analgesia produced by clonidine and morphine was studied in rats. Electrical stimuli were applied to the tail, and analgesia was measured as increase in the threshold voltage that elicited vocalisation. Twenty-two hours after the last of 14 injections of increasing doses of clonidine over 7 days, the acute analgesic effects of both clonidine and morphine were reduced, i.e. tolerance had developed. Pretest vocalisation thresholds (voltage) were unchanged by long-term treatment with clonidine, or, respectively, saline. Contrarywise, acute administration of clonidine enhanced the effect of morphine. The tolerance developed after long-term treatment with clonidine might be associated with changes in brain noradrenaline mechanisms.

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
D003000	Clonidine	An imidazoline sympatholytic agent that stimulates ALPHA-2 ADRENERGIC RECEPTORS and central IMIDAZOLINE RECEPTORS. It is commonly used in the management of HYPERTENSION.	Catapres,Catapresan,Catapressan,Chlophazolin,Clofelin,Clofenil,Clonidine Dihydrochloride,Clonidine Hydrochloride,Clonidine Monohydrobromide,Clonidine Monohydrochloride,Clopheline,Dixarit,Gemiton,Hemiton,Isoglaucon,Klofelin,Klofenil,M-5041T,ST-155,Dihydrochloride, Clonidine,Hydrochloride, Clonidine,M 5041T,M5041T,Monohydrobromide, Clonidine,Monohydrochloride, Clonidine,ST 155,ST155
D004361	Drug Tolerance	Progressive diminution of the susceptibility of a human or animal to the effects of a drug, resulting from its continued administration. It should be differentiated from DRUG RESISTANCE wherein an organism, disease, or tissue fails to respond to the intended effectiveness of a chemical or drug. It should also be differentiated from MAXIMUM TOLERATED DOSE and NO-OBSERVED-ADVERSE-EFFECT LEVEL.	Drug Tolerances,Tolerance, Drug,Tolerances, Drug
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
D013997	Time Factors	Elements of limited time intervals, contributing to particular results or situations.	Time Series,Factor, Time,Time Factor
D014828	Vocalization, Animal	Sounds used in animal communication.	Singing, Animal,Sound Communication, Animal,Vocal Communication, Animal,Animal Singing,Animal Singings,Animal Sound Communication,Animal Sound Communications,Animal Vocal Communication,Animal Vocal Communications,Animal Vocalization,Animal Vocalizations,Communication, Animal Sound,Communication, Animal Vocal,Communications, Animal Sound,Communications, Animal Vocal,Singings, Animal,Sound Communications, Animal,Vocal Communications, Animal,Vocalizations, Animal
D051381	Rats	The common name for the genus Rattus.	Rattus,Rats, Laboratory,Rats, Norway,Rattus norvegicus,Laboratory Rat,Laboratory Rats,Norway Rat,Norway Rats,Rat,Rat, Laboratory,Rat, Norway,norvegicus, Rattus