Chronic cadmium exposure attenuates ethanol-induced hypoalgesia in the adult rat.
Adult male rats were exposed to a diet containing either 100 ppm added cadmium (Cadmium-Diet), or a control diet containing no added chemicals (Control-Diet) for 67 days prior to pain reactivity testing using a tail-flick procedure. Rats were placed in restraining tubes for a 20-min acclimation period, then baseline tail-flick latencies in response to a radiant heat source were measured. Subsequently, half the animals from each group were serially injected intraperitoneally with either 0.5, 1.0, 1.5, or 2.0 g/kg body weight of a 20% v/v ethanol solution, and the other half of the animals were injected with an equivalent volume of saline. Tail-flick latencies were reassessed at 20-min intervals over the next 2 hr. Results indicated dose-dependent ethanol-induced hypoalgesia in the Control-Diet animals for the two highest doses, but ethanol-induced hypoalgesia was evident only at the highest dose for the Cadmium-Diet animals. Further, the magnitude of this hypoalgesic effect was significantly lower for the Cadmium-Diet animals than the Control-Diet animals at the 2.0 g/kg dose. Results are discussed in terms of an attenuation of the pharmacological properties of ethanol by cadmium.
Burkey
R T
RT
Department of Psychology, Texas A&M University, College Station 77843.
Nation
J R
JR
Grover
C A
CA
Bratton
G D
GD
D000818:Animals; D002105:Cadmium Poisoning / Q000503:physiopathology*; D004305:Dose-Response Relationship, Drug; D000431:Ethanol / Q000633:toxicity*; D006987:Hypesthesia / Q000503:physiopathology*; D008297:Male; D009619:Nociceptors / Q000187:drug effects* / Q000503:physiopathology; D017288:Pain Threshold / Q000187:drug effects / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology; D013697:Thermosensing / Q000187:drug effects / Q000502:physiology
D000431:Ethanol