64 



DON TUCKER 



Vomeronasal Receptors 



The vomeronasal system of the rabbit has proved to be a knotty problem. 

 Usually there is no sign of response to odorants, yet in some circumstances 

 there is much variation of vomeronasal neural activity that often appears to 

 be spontaneous. Preparations are highly individualistic. A procedure 

 that serves to modify the activity in one is more often than not without 

 effect in another. Electrical stimulation of the cervical sympathetic nerve, 

 temporary occlusion of the pharynx with finger pressure applied above the 

 larynx, probing of the anterior palate and cannula insertion in the canal 

 of Stenson frequently cause changes in the activity. Spontaneous licking, 

 chewing and swallowing movements under light anesthesia are commonly 

 accompanied by fluctuations of vomeronasal receptor activity. Changes 

 that do occur with introduction of odorous air in the naris seem usually 

 to be produced reflexly and not to be direct responses of vomeronasal 

 receptors to the odorant. 



However, the records of Fig. 18 contain examples of what I believe are 



SWALLOWING 



.^*ia/'MV*^^^' 



l^'/, 



^'ir^W'i^^^ 



"^-v^V^*^^ 



RINGER'S SOL'N > RS 

 PHARYNX OCCLUDED = PO 



GERANIOL SOLN RS RS 



PO PO PO 



\ 



'^^'•VW,^' ^•^'V^ 



V 



vW 



TAP WATER 

 PO 



TW 

 PO 



PO 



Fig. 18. Integrator records of activity recorded from rabbit vomeronasal nerve. 



Solutions were introduced from the canal of Stenson in sufficient quantity to 



appear at the naris. 



responses to odorants in aqueous solution. On the basis of experience 

 with such solutions in the tortoise, the responses with Ringer's solution 

 (contaminating odorants), geranioland tap water (lack of Ca++) seem to be 

 genuine. Through a cannula inserted a few millimeters into the canal of 



