Responses of isolated bronchial muscle to ganglionically active drugs / by D.F. Hawkins and W.D.M. Paton.

  • Hawkins, D. F. (Denis Frank)
Date:
[1958?]
Catalogue details

Licence: In copyright

Credit: Responses of isolated bronchial muscle to ganglionically active drugs / by D.F. Hawkins and W.D.M. Paton. Source: Wellcome Collection.

    5/28 (page 197)
    produced by excitation of bronchodilator ganglion cells situated in close relation to the tracheal muscle. The antagonism between hexamethonium and nicotine appeared to be competitive, progressively higher concentrations of hexamethonium blocking responses to progressively larger doses of nicotine. For example, in one experiment hexamethonium 0*1 /xg/ml. abolished responses to nicotine 50 pg/ml. but merely reduced the responses to nicotine 100 and 200 /xg/ml. On the other hand, in the experiment shown in Fig. 2b a large dose of hexamethonium, 1-0 fjig/ml., abolished responses to nicotine 40, 80 and 200 /xg/ml, whereas nicotine 400 and 1000 p-g/ml. still had an effect. • • • « • Nic Nic mg 1 1 i_i Cocaine 5x 10“® (b) • •• • • o • e • •• Nic Nic Nic N ic Nic mg 1 1 1 11 i-1 Cocaine 10-6 Fig. 3. Guinea-pig tracheal chain, (a) Effect of cocaine 5 x 10-8 on response to nicotine; (b) effect of cocaine 10~6 on response to nicotine. • • Nic 1 Cocaine. If the response to nicotine is mediated by nervous tissue, then it should be reduced or abolished by local anaesthetic drugs. Figure 3 shows the effect of cocaine on the response; the nicotine response was reduced by a low concentration of cocaine (0-05 jag/ml.) and abolished by cocaine in a concen¬ tration of 1*0 pg/ml.