Am.  Jour.  Pharm. 
October,  1920. 
Action  of  Adonis  Vernalis. 
709 
follows  a  more  pronounced  and  more  prolonged  rise.  In  addition  to 
this  feature  there  is  a  marked  slowing  of  the  heart's  rate,  ahd  fre- 
quently a  clearly  demonstrable  increase  in  the  pulse  pressure.  This 
increase  occurs  only  in  case  there  is  a  slowing  of  the  heart's  rate,  and 
is  the  expected  result  upon  the  blood  pressure  of  a  strongly  beating 
heart  which  is  being  slowed  in  rate,  thus  allowing  the  pressure  to  fall 
further  between  beats. 
The  effect  of  adonis  upon  the  frog's  heart  has  been  previously  dis- 
cussed. Tracings  i-A,  B,  C,  and  D  are  typical  of  those  produced 
by  frog  hearts  whose  action  has  been  influenced  by  adonis.  The 
hearts  are  markedly  slowed  in  rate,  show  a  decreased  conduction  be- 
tween the  auricles  and  the  ventricles,  and  present  an  increase  in  the 
strength  of  the  systolic  contraction. 
The  reaction  of  the  mammalian  heart  to  adonis  was  studied  in 
rabbits  and  dogs  by  means  of  the  blood  pressure  tracings,  and  those 
obtained  by  the  myocardiograph.  The  blood  pressure  record  was 
taken  from  the  carotid  artery  of  rabbits,  and  shows  a  slowing  of  the  % 
rate  of  beat  until  a  large  amount  of  drug  has  been  introduced  into  the 
blood  stream,  when  the  heart  becomes  irregular,  many  of  its  beats 
become  inefficient,  and  there  are  large  oscillations  in  the  blood  pres- 
sure resulting,  until  it  finally  falls  as  the  heart  stops  beating.  This 
heart,  however,  upon  examination,  is  found  widely  dilated  and  in  a 
diastolic  condition. 
In  dogs,  a  myocardiographic  record  was  made.  This  demon- 
strated that  the  rate  of  beat  was  slowed  as  in  the  other  experiments, 
both  auricles  and  ventricles  showing  this  effect  previous  to  the  in- 
jection of  sufficient  adonis  to  produce  an  irregular  or  toxic  action 
upon  the  heart.  The  increased  systolic  contraction  becomes  most 
evident  here,  being  especially  prominent  in  the  ventricles.  There  is 
at  times  an  increased  dilatation,  especially  if  the  effect  of  the  vagus 
nerve  is  not  removed  by  atropine.  Section  of  the  vagi  frequently 
has  but  slight  effect,  this  factor  however,  being  somewhat  variable. 
Apparently  adonis  tends  to  a  more  peripheral  stimulation  of  the  vagus 
nerve  than  does  digitalis;  since  in  the  experiments  in  which  section 
of  the  vagi  caused  little  change  in  the  effects  of  adonis,  there  was  a 
noticeable  difference  if  atropine  was  administered.  This  consisted 
in  less  dilatation  of  the  heart,  instead  of  the  increased  dilatation 
usually  produced  by  adonis;  and  also  in  a  more  rapid  rate  of  beat 
instead  of  the  slowed  rate.  This  difference  was  not  noticed  when 
the  same  experiments  were  done  with  digitalis. 
