Passive immunization against nicotine prevents nicotine alleviation of nicotine abstinence syndrome

Passive immunization against nicotine interferes with its locomotor and pre sser effects. The current study determined whether immunization could preve nt another nicotine action: the reversal of nicotine abstinence syndrome. I gG containing 4.4-5.6% nicotine-specific antibody was isolated from rabbits immunized with 3'-amino-methyl-nicotine conjugated to a carrier protein. T wenty rats were rendered dependent by 7 days of subcutaneous infusion of 3. 15 mg/kg/day nicotine (expressed as the base). Upon termination of nicotine infusion, each rat was injected intraperitoneally with 150 mg of IgG from normal serum (n = 13) or from nicotine antiserum (n = 7). Twenty-two and on e-half hours later, all rats were observed over 15 min for baseline nicotin e abstinence signs. Two and one-half hours after baseline observations, sev en of the 13 rats pretreated with control IgG and all seven rats pretreated with nicotine-specific IgG were then challenged by 0.12 mg/kg (sc) nicotin e. The remaining six rats pretreated with control IgG were challenged with saline alone. All rats were then observed again for abstinence signs. Nicot ine injection caused significantly less reduction of abstinence signs in th e immunized rats. The nicotine effect in immunized rats was comparable to t he saline effect in nonimmunized rats. Immunization also significantly redu ced free serum nicotine concentration and nicotine distribution to the brai n. These results raise the possibility that immunization might prevent nico tine consumption from relieving the discomforts of smoking cessation. (C) 2 001 Elsevier Science Inc. All rights reserved.