Drugs with Central Actions 75 



Malmejac (1930) found a secretion after intravenous injection of 

 coramin and pyridin ; they inferred the effect to be central since it 

 was obtained in a submaxillary gland of a dog even when the gland 

 was perfused with blood from another dog. After administration 

 of cocaine to a cat, Blume (1928) observed a profuse salivation 

 lasting for hours. 



Of greater interest than these drugs with more or less generalized 

 central effects are those which activate a physiological mechanism 

 to produce a syndrome in which salivary secretion is one com- 

 ponent. Two instances of drugs causing such effects may be men- 

 tioned : drugs affecting thermoregulation and drugs eliciting nausea 

 and vomiting. 



In dogs, salivation and panting play an important part in the 

 thermoregulatory process. It has been shown that when the body 

 temperature is raised in dogs by the subcutaneous injection of 

 /?-tetrahydronaphthylamine, the submaxillary and sublingual, but 

 not the parotid glands, enter into activity and there is a clear 

 parallelism between the increase in temperature and the rate of 

 salivary flow (Alexandrov, 1939, 1955). Tainter and Cutting (1933) 

 increased the metabolism and the body temperature in different 

 species by injecting dinitrophenol. All the animals were found to 

 make efforts to dissipate heat; the respiration was accelerated and 

 dogs reacted by panting and pouring out large amounts of saliva 

 over the tongue. 



In the nausea syndrome hypersalivation is a conspicuous feature. 

 Drugs with an emetic action therefore cause salivary secretion 

 whether they act reflexly, on the medullary vomiting centre or on 

 the chemoceptive emetic trigger zone of the area postrema. Saliva- 

 tion caused by apomorphine, morphine and related alkaloids (Eddy 

 and Reid, 1934), digitalis glucosides (Wallace and Van Dyke, 1933), 

 quinidine (Ernstene and Lowis, 1933) and veratrum preparations 

 (Borison and Fairbanks, 1952) therefore occurs, not as a separate 

 effect, but as part of the nausea syndrome. 



Numerous drugs have been seen to produce secretion of saliva 

 when injected into the ventricular system of the brain. This effect 

 has been combined with a variety of other symptoms ; the effects 

 have usually been supposed to be elicited from the cells surrounding 

 the third ventricle. Well known are the investigations by Cushing 

 (1931), according to which, pituitrin and pilocarpine, injected into 

 the lateral ventricles in man, cause vascular effects, perspiration, 



