85 



Figure 4. The number of ^ever presses (solid lire) and infusions (32 

 ug/'tg dashed line' is shown as a function of the FR %^ze. 

 The ratios were presented in an ascending order. Each point 

 is a mean of 9 observations (3 rats x 3 sessions] and the 

 vertical lines show the standard. ^. ' 



': ./ \ .' ' ■ ' 



Figure 5. Effects of treatment with necair.ylamine cr he/amethonium on 

 responding maintained by iv nicotine irfusions in 4 rats 

 maintained under a FR 1 schedule. Abscissa: dose cf meca- 

 inylairipe or hexatrethonium given sc. The dose consisted of 

 t^e saline oretreati^ents (see Vethods). Filled bars repre- 

 sent the nuirber of infusions occurring du'-ing the 24 h ses- 

 sion i mediately following a mecatryl amine injection. The 



.„ number of infusions that occurred during the ?4 h following 

 a hexanethonium iniectior (1.5 and 3.0 irg/kg/sc) are repre- 

 sented by the das*^ed l^nes with-'n the oars. Each bar is ar 

 average o' 4 rats. tt-e vertical lires s^-ow the standarc 

 error of the irean. 



Figure 5. The average nutr.ber of infusions in 3 hour blocks is pre- 

 sented for 3 saline (solid lines) and the 3 trecarylamine pre- 

 treatments (O.TS large dashed lines, 1.5 small dashed lir.es 

 and 3.C mg/kg/sc open circles) for 4 rets. The largest Stan- 

 dard error for any 3 h pe-iod during the saline pretreat- 

 irents was 2.12 infusions. 



28 



