Central nicotinic stimulation reduces vascular conductance in the gingiva in anesthetized rats.
OBJECTIVE
The central effects of nicotine on gingival blood flow and vascular conductance were investigated.


BACKGROUND
Nicotine is absorbed in cigarette smoking, which is a risk factor for periodontal disease. Although studies have shown peripheral effects of nicotine on gingival blood flow and gingival vascular conductance, little is known about its central effects.


METHODS
We used laser Doppler flow measurements to investigate the changes of gingival blood flow produced by 5 min intracerebroventricular (i.c.v.) injection of (-)-nicotine ditartrate in rats anesthetized by urethane and alpha-chloralose, along with occasional measurements of the blood pressure from the femoral artery.


RESULTS
The i.c.v. injection of nicotine at 15, 50, and 150 microg reduced the gingival blood flow significantly, compared with saline. The maximal reduction was dose-dependent. Next, we measured the blood pressure and gingival blood flow in the i.c.v. injection of nicotine at 50 microg, to calculate the gingival vascular conductance. The blood pressure was reduced, along with the change of gingival blood flow immediately after the injection, whereas the gingival vascular conductance fell with a time-lag.


CONCLUSIONS
These results suggest that the reduction of gingival blood flow by central nicotinic stimulation is accompanied in part by a change of vascular tonus in the gingiva.
Nakamura
Taiji
T
Department of Physiology, Kyushu Dental College, Kitakyushu, Japan. t_naka@kyu-dent.ac.jp
Ono
Kentaro
K
Honda
Eiko
E
Yokota
Makoto
M
Inenaga
Kiyotoshi
K
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D005881:Gingiva / Q000098:blood supply / Q000187:drug effects*; D017078:Laser-Doppler Flowmetry; D008297:Male; D009538:Nicotine / Q000009:adverse effects / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D012039:Regional Blood Flow
D009538:Nicotine