ABSTRACT
The primary clinical symptom of Paralytic Shellfish Poisoning is acute paralytic illness produced by paralyzing toxins. Paralytic shellfish poison is formed by a mixture of phycotoxins and their toxicity is due to its reversible binding to a receptor site on the voltage-gated sodium channel on excitable cells, thus blocking neuronal transmission. We studied the effect of the gonyautoxin 2/3 epimers by local infiltration in the anal internal sphincter of healthy voluntary adults in order to reduce anal tone. The toxin was injected after prior clinical evaluation, anoscopy and anorectal manometry. Post injection clinical examination, electromyography and anorectal manometry were performed. Resting and voluntary contraction pressures were measured and the anorectal inhibitory and anocortical reflexes were tested by manometry. Blood and urine samples were obtained from each participant, and hemogram, basic metabolic panel, and urinalysis were done both before and one week after the injection. This study shows, for the first time, that gonyautoxin 2/3 reduces the anal tone by relaxing the anal sphincters in 100 % of the participants. Manometric recordings showed a significant decrease in anal maximal voluntary contraction pressure after the toxin injection, dropping to 55.2 ± 6.2 % and 47.0 ± 6.8 % (Mean Value ± Std.Dev.) of the baseline values at 2 minutes and at 24 hours respectively after the injection. Post-injection electromyography showed that activity of the muscle was abolished. We conclude that local administration of gonyautoxin 2/3 to the anal sphincter produces immediate relaxation and a statistically significant decrease in the anal tone (p <0.001)..
Subject(s)
Humans , Male , Adult , Middle Aged , Anal Canal/drug effects , Muscle Relaxants, Central/pharmacology , Muscle Relaxation/drug effects , Muscle Tonus/drug effects , Saxitoxin/pharmacology , Electromyography , Injections, Intramuscular , ManometryABSTRACT
We have already shown the presence of guanidine neurotoxins in calcareous red algae and mussels collected in the Säo Sebastiäo channel State of Säo Paulo,Brazil). It is known that these neurotoxins comprise more than 25 analogues such as tetrodotoxin (TTX) and derivatives plus the paralytic shellfish toxins (PST) found in a variety of marine, freshwater and amphibious species. Filter feeding animals generally possess large amounts of these neurotoxins. The tunicates are sessil marine animals with a high rate of sea water filtration. The tunics and siphons of 50 specimens of Phallusia nigra were dissected and the visceral organs were immersed in methanol containing acetic acid 0.02 N ph 5.0. The extract was prepared by homogenization, filtration and the methanolic phase was concentrated under reduced pressure and defatted with chloroform. The polar phase was evaporated and the residue dissolved in deionized water for further purification in ionic-exchange resin column (Bio-Gel P-2) and HPLC analysis. The extract showed paralytic effects on mouse assay (26.9 MU/100mg) and on crustacean isolated nerve preparations. The chemical analysis for TTX and PST revealed toxins with retention times similar to gonyautoxins, saxitoxins and TTX. These findings are important to explain future toxin envenoming outbreaks on the Brazilian coast.