453 



Psychopharmacology (1992) 108:466-472 



Psychophamiacology 



© Springer- Verlag 1992 



Psychopharmacological effects of smoking a cigarette with typical 

 "tar" and carbon monoxide yields but minimal nicotine* 



John H. Robinson, Walter S. Pritchard, and Riley A. Davis 



Biobchavioral R&D, R.J. Reynolds Tobacco Company, Reynolds Boulevard, Winston-Salem, NC 27102, USA 



Received Febmary 28, 1992 / Final version March 18. 1992 



Abstract. Five male smokers were tested, after 48-h ab- 

 stention from tobacco-product use, smoking a leading 

 "lights" category cigarette (Control - FTC nicotine 

 yield 0.6 mg) and another cigarette yielding similar 

 amounts of "tar" and carbon monoxide (CO), but only 

 0.06 mg nicotine (Test). Heart rate (HR) and the electro- 

 encephalogram (EEG) were monitored before, during 

 and after the smoking of each cigarette. Other measures 

 obtained included the subjects' puffing and breathing 

 behaviors during smoking, plasma nicotine concentra- 

 tions, blood carboxyhemoglobin concentrations and ex- 

 pired-air CO. The results indicated no significant differ- 

 ences in the way the subjects puffed and inhaled the 

 two cigarettes and they were therefore assumed to have 

 inhaled similar amounts of particulate matter and gas- 

 phase components. Plasma nicotine concentrations were 

 significantly higher following smoking of the Control 

 cigarette. HR (percent relative change) increased follow- 

 ing smoking of either cigarette; however, HR increase 

 was significantly greater followmg smoking of the Con- 

 trol cigarette. Smoking the Test cigarette had no effect 

 on the EEG. Smoking the Control cigarette produced 

 a significant increase in beta2 magnitude and a signifi- 

 cant decrease in delta magnitude. This indicates that 

 the effects of smoking on the EEG are a function of 

 nicotine absorbed from cigarette smoke upon inhalation 

 and not a function of inhaled particulate matter, CO, 

 or other gas-phase components. 



Key words: Tar - Carbon monoxide - Nicotine - Psycho- 

 pharmacological effects 



• A nonlinear dynamical analysis of the EEG data presented in 

 this paper appeared previously in Pritchard et al. (1992). An ab- 

 stract of this work was presented at the annual meeting of the 

 Society for Psychophysiological Research. October 1990 in Boston, 

 MA. 



Correspondence lo }.H. Robinson 



The particulate and gas phases of mainstream cigarette 

 smoke contain several thousand compounds (Dube and 

 Green 1982; US DHHS 1983), including such pharma- 

 cologically active compounds as carbon monoxide (CO), 

 acetaldehyde (US DHHS 1988), and alkaloids, including 

 nicotine. Yet, investigations of the psychopharmacologi- 

 cal effects of cigarette smoking have generally concluded 

 that nicotine is the chemical in cigarette smoke responsi- 

 ble for such effects (US DHHS 1988). Evidence support- 

 ing this conclusion has been derived from studies demon- 

 strating that similar blood concentrations of nicotine re- 

 sulting from different methods of administration [ciga- 

 rette smoking, chewing nicotine gum, intravenotis (IV) 

 injection of nicotine] produce similar physiologic re- 

 sponses [e.g., changes in heart rate, blood pressure, elec- 

 troencephalographic (EEG) activity]. Conversely, differ- 

 ent blood concentrations of nicotine result in different 

 physiologic responses. Similarly, variations in the nico- 

 tine yield of cigarettes as well as differences in the puffing 

 and inhalation behaviors of smokers (which all presum- 

 ably affect blood nicotine concentrations) also have been 

 reported to result in differing physiologic responses (see 

 Martin et al. 1987; Adlkofer and Thurau 1991). 



Benowit2 (1986) reviewed studies indicating a 10 ng/ 

 ml rise in plasma nicotine (slow IV infusion) produces 

 a 15 beat per min (BPM) rise in heart rate (HR) in nico- 

 tine-deprived subjects, similar to changes in HR seen 

 following smoking the first cigarette of the day. Nico- 

 tine-gum administration results in cardiovascular 

 changes (heart rate and blood pressure) similar to those 

 "" observed following cigarette smoking (Benowitz 1988). 

 Stalke et al. (1991) showed changes in neurohumoral re- 

 lease following an IV infusion of nicotine that resulted 

 in plasma nicotine concentrations equal to those seen 

 following smoking. Finally, several studies have reported 

 that nicotine gum facilitates cognitive performance in 

 a manner similar to smoking (Parrott and Winder 1989; 

 Hindmarch et al. 1990; Hindmarch et al. 1991; Sher- 

 wood et al. 1990; Kerr et al. 1991 ; Provost and Wood- 

 ward 1991 ; Sherwood et al. 1991) as does chewing buf- 

 fered nicotine tablets (Wesnes and Warburton 1978; 



