Comparison of electroencephalographic changes in response to acute electrical and thermal stimuli with the tail flick and hot plate test in rats administered with opiorphin

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dc.citation.volume18
dc.contributor.authorSingh P
dc.contributor.authorKongara K
dc.contributor.authorHarding D
dc.contributor.authorWard N
dc.contributor.authorDukkipati VSR
dc.contributor.authorJohnson C
dc.contributor.authorChambers P
dc.date.available2018-04-19
dc.date.available2018-04-13
dc.date.issued2018-04-19
dc.description.abstractBackground The objective of this study was to compare the changes in the electroencephalogram (EEG) in response to noxious stimuli with tail flick and hot plate responses of rats administered opiorphin. Methods Female Sprague -Dawley rats (n = 8 per group) randomly received intravenous (IV) injection of morphine (1 mg/kg,) or opiorphin (2 mg/kg,) or saline (0.5 ml,) in each of the three testing methods (EEG, tail flick and hot plate). Each type of test (n = 24 per test) was conducted in different population of rats on separate occasions. The tail flick and hot plate latencies were recorded until 5 min after test drug administration to conscious rats. The EEG was recorded in anaesthetised rats subjected to noxious thermal and electrical stimuli after test drug administration. At the end of 5 min in each of the testing methods rats were administered naloxone subcutaneously (SC) (1 mg/kg) and the test procedure was repeated. Results There was no significant increase in the median frequency and spectral edge frequency (F50 & F95) of EEG, indicators of nociception, of morphine and opiorphin groups after noxious stimulation. Noxious stimuli caused a significant increase in both F50 and F95 of the saline group. An injection of naloxone significantly increased the F50, thus blocking the action of both opiorphin and morphine. There was a significant increase in the tail flick latency after administration of opiorphin and morphine as compared to the baseline values. Rats of morphine group spent significantly longer on the hot plate when compared to those of the opiorphin and saline groups. There was no significant difference in the hot plate latencies of opiorphin and saline groups. Conclusion The results of this study suggest that the analgesic effect of opiorphin occurs at the spinal level and it is not as effective as morphine at supraspinal level. It may be due to rapid degradation of opiorphin or limited ability of opiorphin to cross the blood brain barrier or a higher dose of opiorphin is required for its action in the brain. Pharmacokinetic/pharmacodynamics studies along with in vivo penetration of opiorphin in the cerebrospinal fluid are required for further evaluation of opiorphin analgesia.
dc.description.publication-statusPublished
dc.identifierhttp://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000431076800001&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=c5bb3b2499afac691c2e3c1a83ef6fef
dc.identifierARTN 43
dc.identifier.citationBMC NEUROLOGY, 2018, 18
dc.identifier.doi10.1186/s12883-018-1047-y
dc.identifier.elements-id406530
dc.identifier.harvestedMassey_Dark
dc.identifier.issn1471-2377
dc.publisherBioMed Central Ltd
dc.relation.isPartOfBMC NEUROLOGY
dc.relation.urihttps://bmcneurol.biomedcentral.com/articles/10.1186/s12883-018-1047-y
dc.rights© The Author(s). 2018
dc.subjectOpiorphin
dc.subjectEEG
dc.subjectHot plate test
dc.subjectTail flick test
dc.subject.anzsrc1109 Neurosciences
dc.subject.anzsrc1702 Cognitive Sciences
dc.titleComparison of electroencephalographic changes in response to acute electrical and thermal stimuli with the tail flick and hot plate test in rats administered with opiorphin
dc.typeJournal article
pubs.notesNot known
pubs.organisational-group/Massey University
pubs.organisational-group/Massey University/College of Sciences
pubs.organisational-group/Massey University/College of Sciences/School of Agriculture & Environment
pubs.organisational-group/Massey University/College of Sciences/School of Fundamental Sciences
pubs.organisational-group/Massey University/College of Sciences/School of Veterinary Science
pubs.organisational-group/Massey University/Other
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