1.   Doctors theorize that there are fewer pain receptors.

2.   Professor Bartoshuk remembered that a colleague, Mark Whitehead, had shown that pain receptors in the mouth were wrapped around taste buds.

3.   The beam reaches pain receptors a fraction of an inch under the skin.

4.   The doctors theorized that the density of pain receptors in the ear lobe might be lower than in the thumb.

5.   The implants are not unpleasant for the rats because the brain does not have pain receptors.

6.   There are no pain receptors in the colon, and you can watch the event progress on a television monitor at no extra charge.

7.   They would not have felt pain in any case, because the brain has no pain receptors, Krubitzer said.