Journal of Neurophysiology, Vol 72, Issue 6 2729-2736, Copyright © 1994 by APS
Incomplete suppressive effects of acetylsalicylic acid on the heat sensitization of canine testicular polymodal receptor activities
K. Mizumura, J. Sato, M. Minagawa and T. Kumazawa
Department of Neural Regulation, Nagoya University, Japan.
1. Using canine testis-spermatic nerve preparations in vitro, we studied
the effects of acetylsalicylic acid (ASA), an inhibitor of cyclooxygenase,
on the polymodal receptor response to heat stimulation itself and on the
sensitizing effects on the heat and bradykinin responses induced by strong
heat stimulation (55 degrees C for 30 s). 2. Greater heat responses tended
to be strongly suppressed by ASA (550 microM), with a significant
correlation observed between the response magnitude and the magnitude of
the suppression (r = 0.88 for the response at 45 degrees C; r = 0.83 for
the response at 48 degrees C). The change in the heat response at 48
degrees C from 1.18 +/- 0.19 to 0.62 +/- 0.11 imp/s was statistically
significant (n = 21, P < 0.01). 3. After stimulation at 55 degrees C in
the presence of ASA, resting discharges at 34 degrees C appeared in only 2
of the 21 units tested. The responses at 45 and 48 degrees C, however, were
significantly potentiated after this stimulation (those at 45 degrees C
from 0.12 +/- 0.05 to 2.19 +/- 0.51 imp/s, mean +/- SE; those at 48 degrees
C from 0.62 +/- 0.11 to 2.42 +/- 0.49 imp/s; P < 0.01, n = 21 for both).
Sensitization was observed up to 50 min after stimulation at 55 degrees
C.(ABSTRACT TRUNCATED AT 250 WORDS)
