Effect of anatoxin-a(s) from Anabaena flos-aquae NRC-525-17 on blood pressure, heart rate, respiratory rate, tidal volume, minute volume, and phrenic nerve activity in rats.
The effects of anatoxin-a(s) [antx-a(s)] from the cyanobacterium Anabaena flos-aquae NRC-525-17 on mean arterial blood pressure, heart rate, respiratory rate, tidal volume, minute volume, and phrenic nerve activity were evaluated in anesthetized Sprague-Dawley rats. Anatoxin-a(s) was administered by continuous intravenous infusion. The initial effect of the toxin was to slow the heart rate and reduce arterial blood pressure, followed by much more pronounced reductions in these parameters. The marked decline in heart rate and blood pressure frequently occurred before there was a large decrease in respiratory minute volume [reduced by only 15.4 +/- 3% (mean +/- S.E.) compared to the predose period], suggesting that antx-a(s) has an important muscarinic action on the cardiovascular system in vivo. Phrenic nerve amplitude increased, but, nevertheless, tidal and minute volumes decreased progressively, indicating that antx-a(s), unlike most low-molecular-weight organophosphorus cholinesterase inhibitors, does not have any remarkable inhibitory action on central mediation of respiration.
Cook
W O
WO
Department of Veterinary Biosciences, College of Veterinary Medicine, University of Illinois, Urbana 61801.
Iwamoto
G A
GA
Schaeffer
D J
DJ
Beasley
V R
VR
D000818:Animals; D001427:Bacterial Toxins; D001794:Blood Pressure / Q000187:drug effects*; D006224:Cricetinae; D000458:Cyanobacteria; D000087522:Cyanobacteria Toxins; D006339:Heart Rate / Q000187:drug effects*; D008176:Lung Volume Measurements; D008297:Male; D008387:Marine Toxins / Q000494:pharmacology*; D052998:Microcystins; D009132:Muscles / Q000187:drug effects; D010791:Phrenic Nerve / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains; D012119:Respiration / Q000187:drug effects*; D012798:Sialorrhea / Q000139:chemically induced; D013990:Tidal Volume / Q000187:drug effects*; D014326:Tropanes
D001427:Bacterial Toxins; D000087522:Cyanobacteria Toxins; D008387:Marine Toxins; D052998:Microcystins; D014326:Tropanes; C509783:anatoxin a