172 PHYSIOLOGICAL TRIGGERS 



atropine, dibenamine and Nembutal, that the hypophysis was ordinarily stim- 

 ulated via the nervous system on the day of proestrus. Under controlled lighting 

 conditions the stimulation occurred between 24 p.m. on that day, and the 

 process took from 20^35 minutes. More recently with Barraclough (2-4) we 

 have found that morphine, reserpine and chlorpromazine all block the process, 



w.ryA*MM1^«^,^MA^W%tp^^KM^/,^^ 



L.A.H. 

 M.A.H 

 3.34 



V/*Vl*Al•■«V^'M/W/■wvr.A^%■^v^v^^'A^."A''v-*v^^rv^/~.vw^ 





-Speeded record x4- 



3'.4I 60mm/Sec . ^^^ ■ 



3:47 



353 



3.54 r 



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5 Sees 



Fig. 7. EF'^G changes observed in rat lateral anterior liypothalamus (LAH) in llie critical 

 period of the day of proestrus during which the adenoh\i)oi)h_\sis is stimulated to release 

 pituitary ovulating hormone. MAH, medial anterior hypothalamus. 



in most cases apparently by raising the threshold of the reticular activating 

 center (32). IMorphine is of special interest since this drug has been known for 

 years to induce amenorrhea and infertility in the human female. 



In our laboratory Mr. Critchlow (7) has been recording from various regions 

 of the cerebral cortex and brainstem of the rat during various hours and days of 



