text: Yo, check it out, I got some science to drop,
  Talkin' 'bout the action potential, let me make it pop.
  Histamine-induced slow action potentials, that's the game,
  And nicotine's rollin' in, bringin' it with no shame.
  
  Nicotine, in the mix, concentratin' like a pro,
  Potentiating APD, makin' that force of contraction grow.
  Guinea pig papillary muscles, they feel the vibe,
  Concentration-dependent, it's how nicotine thrives.
  
  But hold up, atropine's here, changin' up the game,
  Nicotine, concentration-dependent, feelin' the strain.
  Action potential amplitude, APD, and Vmax take a hit,
  Even the force of contraction feels the nicotine's grip.
  
  Catecholamine-depleted muscles, reserpine's in play,
  Nicotine's suppressin', takin' control in its own way.
  0.6 mmol.L-1, it's showtime, slow action potentials arise,
  And the force of contraction, it's got a big surprise.
  
  Verapamil steps up, antagonizin' the effects,
  Puttin' a stop to nicotine, no time for respect.
  Nicotine-induced SAP, APA's in the mix,
  Linear relationship with calcium, that's the fix.
  
  APA and 1g [Ca2+]0, they're tight,
  A 10-fold change, a slope of 23.2 mV, that's right.
  Nicotine's got a trick, it's all about release,
  Catecholamines in the myocardium, bringin' the peace.
  
  So there you have it, the effects of nicotine revealed,
  Myocardium's rockin', with every beat it's sealed.
  Science droppin' knowledge, breakin' it down for you,
  Nicotine's got the power, with its own unique brew.