ACTION OF PILOCAKPUS AND PILOCAKPINE 441 



PiLOCAEPiNE^ NiTKAS, Pilocarpine Nitrate. (U.S.&B.P.) 



Colorless, odorless, faintly bitter-tasting crystals, soluble 

 in four parts of water. 



Dose. — Same as for hydrochloride. 



ACTION OF PIIiOCAEPUS AND PILOCARPINE. 



Internal. — Alimentary Canal. — 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. The 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 increases leucocyte formation 

 in the blood. In the lower animals the alkaloid stimulates 

 the vagus endings in the heart. This action is succeeded by 

 depression of the vagus terminations and, after large doses, 

 by depression of the heart muscles and vagus centres. 



The pulse is then at first slow, next it becomes acceler- 

 ated, and finally slow and weak with loss of tension. 



In man, and occasionally in dogs, the pulse is often at 

 the beginning frequent and the vascular tension is increased. 

 The physiological reasons for this are unknown. 



Respiration. — The respiration is not directly affected by 

 the drug, in moderate doses, but the bronchial secretions are 

 greatly increased, the bronchioles are much constricted, and 

 ■in poisoning there are, in consequence, oedema of the lungs 

 and dyspnoea. Weakness of the circulation and contraction 



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