Study type: Medical/biological study (experimental study)

The effects of melatonin on electrical field stimulation-evoked biphasic twitch responses in the ipsilateral and contralateral rat vasa deferentia after unilateral testicular torsion/detorsion. tech./dosim.

Published in: Naunyn Schmiedebergs Arch Pharmacol 2005; 371 (5): 351-358

Aim of study (acc. to author)

To determine whether the electrical field stimulation-evoked biphasic contractions are altered in ipsilateral and contralateral rat vasa deferentia obtained from animals exposed to the unilateral testicular torsion/detorsion procedure. An impairment in vas deferens motility after unilateral testicular torsion/detorsion is known.

Background/further details

Unilateral testicular torsion is a clinical syndrome caused by torsion of the spermatic cord and is treated by a surgical detorsion procedure. There are no data in the literature examining the motility of the vas deferens after the torsion/detorsion procedure.
Animals were subjected to torsion of the left testis (rotated by twisting clockwise 720°) for 2 h and then detorsion was performed. Contractility studies were carried out 2 h or 24 h after detorsion. Vas deferens strips were prepared from both the ipsilateral and the contralateral site 2 h or 24 h after the detorsion procedure. The effects of melatonin (a strong antioxidant) on the contractile responses were also evaluated. For the melatonin-treated animals the same protocol was repeated.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 1–64 Hz
Modulation type: pulsed
Exposure duration: intermittent, every 5 min
-

General information

Rats were divided into three groups of 6 animals each: Group 1 was used for control in which the animals were not subjected to any medical or surgical procedure, group 2 was stimulated with electric field whereas group 3 served as sham group.

Exposure 1

Main characteristics
Frequency 1–64 Hz
Type
Waveform
Exposure duration intermittent, every 5 min
Additional info The following frequencies were used: 1 Hz, 2 Hz, 4 Hz, 8 Hz, 16 Hz, 32 Hz and 64 Hz.
Modulation
Modulation type pulsed
Pulse width 1 ms
Additional info

10 s trains of pulses

Exposure setup
Exposure source
Parameters

No parameters are specified for this exposure.

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • during exposure

Main outcome of study (acc. to author)

The contractions of the vas deferens are biphasic: the first phase is attributed to ATP acting at P2X receptors and the second phase to noradrenaline at alpha1-receptors.
In the ipsilateral vas deferens both phases of electrical field stimulation-evoked contractions were decreased after torsion/detorsion. Melatonin treatment increased torsion/detorsion-induced reduction of both phases of contractions after 2 h and 24 h.
In the contralateral vas deferens, the first phase of electrical field stimulation-evoked contractions was not altered, while the second phase of contractions was diminished 2 h and 24 h after detorsion. Although melatonin decreased the second phase of contractions 2 h and 24 h after detorsion, it reduced the first phase of contractions only 2 h after detorsion.
These data suggest that melatonin produces an inhibition on electrical field stimulation-evoked biphasic twitch responses in the ipsilateral and contralateral rat vasa deferentia following unilateral testicular torsion/detorsion in the rat.

Study character:

Study funded by