Time-dependent changes in cardiovascular function during copulatory behavior induced by the hand method in the male dog.
OBJECTIVE
Ejaculation in the male dog consists of three fractions. Observation of behavior and measurement of heart rate (HR), and plasma noradrenaline (NA) and adrenaline (Ad) concentrations were researched sequentially, and a fundamental examination of the features of sympathetic nerve activity during copulatory behavior induced by the hand method in the male dog was undertaken.


METHODS
We investigated the breeding capability of male dogs. HR, plasma NA level and plasma Ad levels were measured during ejaculation induced by the hand method.


RESULTS
HR was 125.8 ± 6.0 beats/min at rest, and peaked during mounting at 195.2 ± 8.2 beats/min. Moreover, HR at 3 min after the first fraction decreased to values similar to those at rest. Plasma NA and Ad concentrations during copulatory behavior induced by the hand method did not differ significantly from those at rest. However, although there was no significant difference, plasma NA concentration during ejaculation of the third fraction peaked at about 1.8 times the baseline value.


CONCLUSIONS
In the male dog, excitation of sympathetic nerves of long duration during erection of the penis and ejaculation is questionable. However, inhibition of sympathetic nerves and activation of parasympathetic nerves is thought to occur during erection of the penis and ejaculation.
Laboratory Animal Research Center, Dokkyo Medical University, 880 Kitakobayashi, Mibu, Tochigi 321-0293 Japan.
Misao
M
Terada
Kitayama Labes Co., Ltd., Nagano, Japan.
Yatsuka
Y
Horii
Japan Racing Association, Hidaka Training and Research Center, Hokkaido, Japan.
Fumio
F
Sato
Department of Veterinary Anatomy, Kitasato University, Aomori, Japan.
Kazumi
K
Taniguchi
Department of Reproduction, Nippon Veterinary and Life Science University, Tokyo, Japan.
Tatsuya
T
Hori
Department of Reproduction, Nippon Veterinary and Life Science University, Tokyo, Japan.
Eiichi
E
Kawakami
Department of Reproduction, Nippon Veterinary and Life Science University, Tokyo, Japan.
Toshihiko
T
Tsutsui
Division of Laboratory Animal Science, Nippon Medical School, Tokyo, Japan.
Toshio
T
Akimoto
Laboratory Animal Research Center, Dokkyo Medical University, 880 Kitakobayashi, Mibu, Tochigi 321-0293 Japan.
Motoo
M
Shinoda
Behavioral Neuroscience Laboratory, Nippon Veterinary and Life Science University, Tokyo, Japan.
Toru R
TR
Saito
Adrenaline; Hand method; Heart rate; Male dog; Noradrenaline