A thought provoking bit of information using a kotegaeshi response to a mune tsuki. There are are a number of pressure points located on the forearm ,wrist, and hand. The series on the top inside of the forearm/wrist/hand releases the fist; the point used in this technique is midway between the elbow and wrist. As Nage's leading 'sword hand' makes contact with uke's out-thrust forearm this pressure point is hit. Nage's hand then slides down over the wrist/hand, with the thumb placed just below uke's ring finger. The series of pressure points on the bottom forearm/wrist/hand releases the wrist; the point used in this technique is located in the "V" formed by the bones between the little finger and the ring finger(It is most painful when activated with the tip of nage's thumb).
Of course, Nage could continue to hold this point as the technique is completed(with a standing pin, for example). Upon further investigation you may discover more ["hidden"] Atemi in AIKIDO techniques than you were aware of. Hmmm... (I highly recommend George Dillman's seminars/media)