ACTION OF PILOCARPUS AND PILOCARPINE 4 7 



Pilocarpine Nitras. Pilocarpine Nitrate. (B. P.) 

 Dosfi, — Same as for hydrochlorate. 



ACTION OF pilocarpus AND PILOCARPINE. 



Interned. — Alimentary Caned. — Pilocarpine increases 

 enormously salivary secretion, and, in a less degree, the 

 gastric and intestinal secretions. It stimulates peristaltic 

 action of the stomach and bowels as well, and acts as a pur- 

 gative. Salivation is due to direct excitation of the secre- 

 tory nerve (chorda tympani) endings and the gland cells. 

 Salivation occurs when pilocarpine is injected into the gland 

 and prevented from entering the general circulation ; also 

 when the secretory nerves are severed. The action on the 

 salivary glands is set aside by atropine. The parotid, sub- 

 maxillary, and sublingual glands, become somewhat tense 

 and tender under the influence of pilocarpine,* and the saliva 

 is rich in salts and ptyaline, and contains a slight excess of 

 urea. Thn unstriped muscle of the stomach and intestines 

 is stimulated by pilocarpine through its action on the effer- 

 ent nerve endings and muscular tissue. 



Circulation. — Pilocarpine is absorbed, but exerts no 

 action on the blood. In toxic doses the alkaloid is a heart 

 depressant, but in moderate amount slows the pulse rate. 

 In man the pulse is quick and the blood tension lowered. 

 The effect on the domestic animals is probably due to 

 stimulation of the peripheral vagi or inhibitory cardiac 

 ganglia, although Ringer's experiments proved that the 

 ventricular contractions of the frog's heart were slowed by 

 pilocarpine when freed from the inhibitory ganglia, and h-^ 

 attributes its action to stimulation of the heart muscle jind 

 motor ganglia situated therein. In poisoning, the heart is 

 enfeebled and slow, and there is vasomotor paralysis. Atro- 

 pine antagonizes the action of pilocarpine on the heart. 



Respiration. — The respiration" is not directly affected by 

 the drug, but the bronchial secretions are greatly increased, 

 and in poisoning there are, in consequence, oedema of the 

 lungs and dyspnoea. 



