A History of High Dose Nicotine Self-administration Increases the Rate of Self-administration at Low Nicotine Doses.
Year: 2014
Type: dissertation
Abstract: Introduction: FDA-mandated product standards that drastically reduce nicotine content in cigarettes may result in decreased smoking and thus, improved health outcomes for millions of U.S. smokers. One issue is whether the rate of smoking at reduced nicotine contents would be different for current smokers from individuals who start smoking for the first time at the reduced content. Method: 48 rats were given the opportunity to self-administer at one of four low nicotine doses (15, 7.5, 3.75, 0.0 µg/kg/infusion) before and after self-administering a higher dose of nicotine (60 µg/kg/infusion). A second group of 57 rats acquired self-administration at the high nicotine dose before experiencing reduction. A cocktail of other cigarette constituents was included in the vehicle and remained constant across the study. Results: The rate of self-administration across the low doses (including vehicle) was higher following self-administration of a high dose. Rates of self-administration following reduction from the high nicotine dose were the same regardless of whether the rats originally acquired at a low dose or the high dose. The effect of self-administering a high nicotine dose was highest for a threshold dose (7.5 µg/kg/infusion). Discussion: The present study suggests rate of self-administering low nicotine doses may be increased by having a history of high dose self-administration. The large effect at a threshold nicotine dose may indicate a shift in the threshold for maintaining behavior as a result of experience with higher doses of nicotine. These data would support the idea that current smokers may smoke at a higher intensity following nicotine reduction than individuals who begin smoking for the first time at the reduced rate. Furthermore, the rate of self-administration following reduction was the same regardless of whether rats acquired at the high dose of nicotine or experienced a low dose before being changed over to a high nicotine dose.
Author: Tracy T. Smith
Language: English
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W120245984