title: Antinociceptive action of bradykinin and related kinins of larger molecular weights by the intraventricular route.
abstract: 1. It was shown previously that bradykinin (Bk) when given intraventricularly increases the threshold of electrical stimulation of dental pulp in the rabbit.2. Bradykinin derivatives with increasing molecular weights (lysyl-Bk (L-Bk), methionyl-lysyl-Bk (ML-Bk) and glycyl-arginyl-methionyl-lysyl-Bk (GAML-Bk)) were found to produce effects of decreasing intensity on the threshold of electrical stimulation according to the following scale: Bk (1.00)>L-Bk (0.28)>ML-Bk (0.060)>GAML-Bk (0.047).3. The four peptides had similar relative activities on the guinea-pig ileum but an inverse relationship in their effects on vascular permeability and rat blood pressure.4. The discrimination index, increase in vascular permeability/antinociceptive effect rose to values of the order of 170 to 550, taking Bk as the reference peptide (potency=1.00).5. We conclude that the increase in threshold of electrical stimulation could not be due to an increase in vascular permeability or decrease of blood pressure.
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D001808:Blood Vessels / Q000187:drug effects; D001920:Bradykinin / Q000008:administration & dosage / Q000494:pharmacology*; D002199:Capillary Permeability / Q000187:drug effects; D002552:Cerebral Ventricles; D003782:Dental Pulp / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004386:Duodenum / Q000187:drug effects; D004558:Electric Stimulation; D005260:Female; D005283:Fentanyl / Q000494:pharmacology; D006168:Guinea Pigs; D007082:Ileum / Q000187:drug effects; D066298:In Vitro Techniques; D007267:Injections; D007705:Kinins / Q000008:administration & dosage / Q000494:pharmacology*; D008970:Molecular Weight; D009020:Morphine / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects; D010455:Peptides / Q000494:pharmacology; D011817:Rabbits; D051381:Rats; D012867:Skin / Q000098:blood supply; D013329:Structure-Activity Relationship; D014599:Uterus / Q000187:drug effects
chemical_list: D007705:Kinins; D010455:Peptides; D009020:Morphine; D001920:Bradykinin; D005283:Fentanyl