Biomaterial Database

Relative analgesic potency of mu, delta and kappa opioids after spinal administration in amphibians. 1996

C W Stevens

Department of Pharmacology and Physiology, Oklahoma State University, College of Osteopathic Medicine, Tulsa, USA.

The analgesic effects of 12 opioid agonists in amphibians were measured using the acetic acid test. Spinal administration of dermorphin, [D-Ala2,NMePhe4,Gly-ol]-enkephalin, fentanyl and morphine (mu opioids); [D-Ser2,Leu5-Thr6]-enkephalin, [D-Ala2,D-Leu5]-enkephalin, [D-Pen2,D-Pen5]-enkephalin and deltorphin (delta opioids); and Cl977 [(5R)-(544 alpha,744 alpha,845 beta)-N-methyl-N-[7-(1-pyrrolidinyl)-1- oxaspiro[4,5]dec-8yl]-4-benzofuranacetamide monohydrochloride, bremazocine), U50488 (trans-3,4-dichloro-N-methyl-N-[2-(1-pyrrolidinyl)- cyclohexyl]benzeneacetamide methanesulfonate) and nalorphine (kappa opioids) produced a dose-dependent and long-lasting analgesia in the Northern grass frog, Rana pipiens. With all opioids, time course experiments showed that this analgesic effect lasted for at least 4 hr, with no untoward effects observed within each dosage range used. The analgesic effects of the 12 opioids were blocked by systemic naltrexone pretreatment. Comparison of dose-response curves demonstrated that the rank order of potency was such that, in general, mu opioids > delta opioids > kappa opioids. Dose-response curves obtained in the presence of a fixed dose of naltrexone showed the greatest shift for [D-Ser2,Leu5-Thr6]-enkephalin, less so for [D-Ala2,NMePhe4,Gly-ol]-enkephalin and the least shift for bremazocine. ED50 values for mu and delta opioids in the amphibian acetic acid test were significantly correlated to ED50 values of the same opioids reported in the literature for the rodent TF test. These results show that a spinal site of opioid analgesia is present in amphibians and supports the utility of this alternative, nonmammalian model for studies of opioid analgesia and pain research.

UI	MeSH Term	Description	Entries
D007278	Injections, Spinal	Introduction of therapeutic agents into the spinal region using a needle and syringe.	Injections, Intraspinal,Injections, Intrathecal,Intraspinal Injections,Intrathecal Injections,Spinal Injections,Injection, Intraspinal,Injection, Intrathecal,Injection, Spinal,Intraspinal Injection,Intrathecal Injection,Spinal Injection
D009271	Naltrexone	Derivative of noroxymorphone that is the N-cyclopropylmethyl congener of NALOXONE. It is a narcotic antagonist that is effective orally, longer lasting and more potent than naloxone, and has been proposed for the treatment of heroin addiction. The FDA has approved naltrexone for the treatment of alcohol dependence.	Antaxone,Celupan,EN-1639A,Nalorex,Naltrexone Hydrochloride,Nemexin,ReVia,Trexan,EN 1639A,EN1639A
D011894	Rana pipiens	A highly variable species of the family Ranidae in Canada, the United States and Central America. It is the most widely used Anuran in biomedical research.	Frog, Leopard,Leopard Frog,Lithobates pipiens,Frogs, Leopard,Leopard Frogs
D004305	Dose-Response Relationship, Drug	The relationship between the dose of an administered drug and the response of the organism to the drug.	Dose Response Relationship, Drug,Dose-Response Relationships, Drug,Drug Dose-Response Relationship,Drug Dose-Response Relationships,Relationship, Drug Dose-Response,Relationships, Drug Dose-Response
D000701	Analgesics, Opioid	Compounds with activity like OPIATE ALKALOIDS, acting at OPIOID RECEPTORS. Properties include induction of ANALGESIA or NARCOSIS.	Opioid,Opioid Analgesic,Opioid Analgesics,Opioids,Full Opioid Agonists,Opioid Full Agonists,Opioid Mixed Agonist-Antagonists,Opioid Partial Agonists,Partial Opioid Agonists,Agonist-Antagonists, Opioid Mixed,Agonists, Full Opioid,Agonists, Opioid Full,Agonists, Opioid Partial,Agonists, Partial Opioid,Analgesic, Opioid,Full Agonists, Opioid,Mixed Agonist-Antagonists, Opioid,Opioid Agonists, Full,Opioid Agonists, Partial,Opioid Mixed Agonist Antagonists,Partial Agonists, Opioid
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
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
D017465	Receptors, Opioid, delta	A class of opioid receptors recognized by its pharmacological profile. Delta opioid receptors bind endorphins and enkephalins with approximately equal affinity and have less affinity for dynorphins.	Opioid Receptors, delta,Receptors, delta,Receptors, delta Opioid,delta Receptors,delta Opioid Receptor,delta Receptor,Opioid Receptor, delta,Receptor, delta,Receptor, delta Opioid,delta Opioid Receptors
D017473	Receptors, Opioid, kappa	A class of opioid receptors recognized by its pharmacological profile. Kappa opioid receptors bind dynorphins with a higher affinity than endorphins which are themselves preferred to enkephalins.	Opioid Receptors, kappa,Receptors, kappa,Receptors, kappa Opioid,kappa Receptors,kappa Opioid Receptor,kappa Receptor,Opioid Receptor, kappa,Receptor, kappa,Receptor, kappa Opioid,kappa Opioid Receptors