Development from Suckling to Chewing in Guinea Pig 2. Effect of Major Salivary Glands

Abstract

The purpose of the present study was to clarify the role of the major salivary glands on the transition from suckling to chewing in new born guinea pigs.
Fifty five guinea pigs were used and the major salivary glands such as the submandibular, sublingual and parotid were surgically removed under an anesthesia with Ketamine (2 mg/kg body weight, i. p. ) 7 days after birth. Depending on the removal of single or combined salivary gland, the animals were grouped into following seven, group 1 submandibular only, group 2 sublingual only, group 3parotid only, group 4 submandibular and sublingual, group 5 submandibular and parotid, group 6 sublingual and parotid, and group 7 control, to which only surgery necessary for salivary gland removal was performed.
After removal of the salivary glands, the intraoral pressure was recorded by a pressure transducer (Gould statham Co., P231-D) and the jaw movements by Saphon Visi-Trainer CII (Tokyo-Shizai Co. ). Transition time from suckling to chewing was then evaluated based on the intraoral pressure and the jaw movements as reported in our previous paper.
There was no difference in the beginning of chewing movement between group 3 and group 7. While it was delayed for 1 day in group 2, and for 2 days in group 1, in group 4, it was exceptionaly delayed for 12 days. There were some effects in every group of the suckling period. It was delayed for 3 days in group 2, for 4 days in group 3, and for 7 days in group 1.
These results disclosed that the salivary gland, particularly the submandibular gland plays an important role in the transition from suckling to chewing, and it is also suggested that the quantity of saliva may be related factors on the transition from suckling to chewing.