Millington, William R.Feleder, Carlos2023-04-112023-04-112016-03-21Millington, W. R. vd. (2016). "The initial fall in arterial pressure evoked by endotoxin is mediated by the ventrolateral periaqueductal gray". Clinical and Experimental Pharmacology and Physiology, 43(6), 612-615.1440-1681https://doi.org/10.1111/1440-1681.12573https://onlinelibrary.wiley.com/doi/10.1111/1440-1681.12573http://hdl.handle.net/11452/32309This study tested the hypothesis that the initial fall in arterial pressure evoked by lipopolysaccharide (LPS) is mediated by the ventrolateral column of the midbrain periaqueductal gray region (vlPAG). To test this hypothesis, the local anaesthetic lidocaine (2%; 0.1L, 0.2L or 1.0L), the delta opioid receptor antagonist naltrindole (2nmol) or saline was microinjected into the vlPAG of isoflurane-anaesthetized rats bilaterally and LPS (1mg/kg) or saline was administered intravenously 2min later. Both lidocaine and naltrindole inhibited LPS-evoked hypotension significantly but did not affect arterial pressure in saline-treated control animals. Neither lidocaine nor naltrindole altered heart rate significantly in either LPS-treated or control animals. Microinjection of lidocaine or naltrindole into the dorsolateral PAG was ineffective. These data indicate that the vlPAG plays an important role in the initiation of endotoxic hypotension and further show that delta opioid receptors in the vlPAG participate in the response.eninfo:eu-repo/semantics/openAccessPharmacology & pharmacyPhysiologyDelta receptorEndotoxinEndotoxin shockLipopolysaccharideOpioid receptorPeriaqueductal grayPreoptic areaAnterior hypothalamic areaSympathetic-nerve activityDelta-opioid receptorsCardiovascular-responsesInduced hypotensionProjection pathwayPreoptic areaRatsShockNucleusAnimalsArterial pressureEndotoxinsInjections, intraventricularLipopolysaccharidesMalePeriaqueductal grayRatsRats, sprague-dawleyArticle0003759366000042-s2.0-8496490205261261543627009880Pharmacology & pharmacyPhysiologyPeriaqueductal Gray; Animals; Escape ReactionDelta opiate receptorEndotoxinIsofluraneLidocaineLipopolysaccharideNaltrindoleSodium chlorideEndotoxinAnimal experimentArterial pressureArticleControlled studyHeart rateHypotensionMaleNonhumanPeriaqueductal gray matterRatTreatment responseAnimalArterial pressureDrug effectsIntracerebroventricular drug administrationPeriaqueductal gray matterPhysiologySprague dawley rat