Reactive hyperemia reflects a compensatory vasodilation response of the local vasculature in ischemic tissue. The purpose of this study is to clarify the mechanism of regulation of this response in gingival circulation by using pharmacological analysis of reactive hyperemia and histochemical analysis of gingival tissue. Application of pressure to the gingiva was used to create temporary ischemia, and gingival blood flow was measured after pressure release. Reactive hyperemia increased in proportion to the duration of pressure. Systemic hemodynamics remained unaffected by the stimulus; therefore, the gingival reactive hyperemia reflected a local adjustment in circulation. Gingival reactive hyperemia was significantly suppressed by nitric oxide (NO) synthase inhibitors, especially the neural NO synthase-selective antagonist 7-nitroindazole, but not by anticholinergic drugs, β-blockers, or antihistaminergic drugs. Moreover, immunohistochemical staining for neural NO synthase and histochemical staining for NADPH diaphorase activity were both positive in the gingival perivascular region. These histochemical and pharmacological analyses show that reactive hyperemia following pressure release is mediated by NO-induced vasodilation. Furthermore, histochemical analysis strongly suggests that NO originates from nitrergic nerves. Therefore, NO may play an important role in the neural regulation of local circulation in gingival tissue ischemia.

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This study compared the growth and development of the physique and physical fitness of young Japanese males who belong to sports clubs and those who did not based on longitudinal data obtained over four years. Physique and physical fitness tests were administered to 253 healthy male technical college students four times from the 9 to 12 grade. Subjects were divided into two groups: those who did not belong to an extra-curricular sports club (control group: CG, n = 126), and those who belonged to sports clubs (exercise group: EG, n = 127). Sit-ups, side-stepping, 20 m shuttle run, 50 m run and handball throwing tests and a total score were superior in the EG compared to the CG. Differences between the two groups in body mass, Rohrer's index, six physical fitness tests (except for a handgrip and 50 m run), and the total score increased with grade. The CG was inferior in overall physical fitness to the EG, especially in whole body endurance. It is highly possible that sports club activities significantly and positively affect the growth and development young males during the growth period under 19-years-old and that inactivity inhibits the development of whole body endurance.

This study aimed to examine the influence of exercise habits and physical fitness level on subjective fatigue symptoms (SFS) in adolescent students. Four hundred and one healthy young male adults (age: 16.5 +/- 1.2 yr) participated in the physical fitness test of the Ministry of Education, Culture, Sports, Science and Technology in Japan and responded to the questionnaire on exercise habits and SFS. SFS questionnaire was conducted 6 times with a week interval during the physical fitness test. SFS was compared among groups with different physical fitness levels and exercise habit. Significant differences were found in difficulty with concentrated thinking, languor and low vigor, with the high physical fitness group having lower values of the three fatigue factors than the low physical fitness group regardless of affiliation with sports club and gyms, exercise frequency and time. SFS is largely affected by physical fitness level but very little by exercise habits