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A comparison of the protective effects of neostigmine and physostigmine on Delphinium barbeyi poisoning in cattle
Author(s) -
Green Benedict Thomas,
Cook Daniel,
Pfister James A.,
Welch Kevin D.,
Lee Stephen T.,
Stegelmeier Bryan L.,
Gardner Dale R.,
Panter Kip E.
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.1137.6
Subject(s) - neostigmine , physostigmine , curare , heart rate , chemistry , atropine , zoology , cholinesterase , anesthesia , toxicology , pharmacology , acetylcholine , medicine , biology , blood pressure
The N ‐(methylsuccinimido) anthranoyllycoctonine type (MSAL) alkaloids in toxic larkspur spp. are potent nicotinic cholinergic receptor antagonists with curare‐like effects at high doses. We addressed the hypothesis that neostigmine would be as effective as physostigmine, at reversing the effects of MSAL alkaloids from D. barbeyi in beef cattle. Cattle were dosed p.o. with dried‐ground larkspur containing 5.8 mg/g MSAL alkaloids and changes in heart rate and the evoked‐electromyographic response of the anal sphincter was monitored at 24 h. Treatment with MSAL alkaloids over a dose‐range of 0.45 – 11.77 mg/kg resulted in a dose‐dependent increase in heart rate, and a decrease muscle tone. Neostigmine (0.04 mg/kg) given i.v., 24 h after dosing with 10.38 mg/kg MSAL alkaloids decreased heart rate but had no effect on muscle tone. Neostigmine (0.02 mg/kg) given i.m. reversed the curare‐like effects of a high dose (14.54 mg/kg) of MSAL alkaloids within 15 minutes. Conversely, physostigmine (0.04 mg/kg) given i.v., 24 h after dosing with 10.38 mg/kg MSAL alkaloids had no effect on heart rate but increased muscle tone by 2‐fold. These results suggest that in an experimental setting, neostigmine is more effective than physostigmine at reversing the peripheral effects of MSAL alkaloids on the heart and that it can reverse the curare‐like effects of high doses of MSAL alkaloids in cattle. Research supported by USDA‐ARS.