Nociceptive and edematogenic responses elicited by a crude bristle extract of Lonomia obliqua caterpillars

• Published in: Toxicon (Oxford) Vol. 43; no. 3; pp. 273 - 278
• Main Authors: Bastos, Lúcia de Castro, Veiga, Ana Beatriz Gorini, Guimarães, Jorge A, Tonussi, Carlos Rogério
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.03.2004; Elsevier Science
• Subjects: Aftersensation; Allodynia; Animal poisons toxicology. Antivenoms; Animals; Anti-Inflammatory Agents, Non-Steroidal; Arthropod Venoms - administration & dosage; Arthropod Venoms - toxicity; Biological and medical sciences; Dose-Response Relationship, Drug; Edema - chemically induced; Guanethidine; Hematuria; Indomethacin; Inflammation; Lonomia obliqua; Loratadine; Male; Medical sciences; Pain; Pain - chemically induced; Rats; Rats, Wistar; Saturniidae; Toxicology; Allodynia; Inflammation; Pain; Hematuria; Aftersensation; Extract
• ISSN: 0041-0101; 1879-3150
• DOI: 10.1016/j.toxicon.2003.12.003

Lyophilized Lonomia obliqua crude bristle extract (LOCBE) diluted in physiological saline (15, 35 and 50 μg of protein/paw) was injected in the plantar surface of the hind paw of the rat, causing a nociceptive response which lasted from 30 to a maximum of 50 min, peaking in the first 5 min. The animals also presented hematuria and nasal bleeding. Nociception was inhibited by indomethacin pretreatment (2.5 mg/kg, i.p., 60 min before), but not by guanethidine (30 mg/kg/day, s.c., for 3 days) or loratadine (5 mg/kg, p.o., 60 min before). LOCBE injection also produced paw edema peaking 1 h after injection and lasting for 6 h. Loratadine pretreatment, but neither guanethidine nor indomethacin, reduced edema. After the period of overt nociception, a nociceptive aftersensation response could be evoked up to 6 h after by immersing the paw into cold water (15 °C) for 10 s. Capsaicin (1.6 μg), formalin (0.5%) or prostaglandin E 2 (500 ng) did not produce the same aftersensation phenomenon. These results suggest that LOCBE-induced nociception is largely facilitated by prostaglandin production, and edematogenic response seems to be facilitated by prostanoids and histamine. Finally, LOCBE induced a state of sensitization to cold, which seemed to be specific as it was not caused by other noxious chemicals.