Original scientific paper
https://doi.org/10.3325/cmj.2017.58.141
Identification of myoelectric signals of pregnant rat uterus: new method to detect myometrial contraction
Kálmán F. Szűcs
; Department of Pharmacodynamics and Biopharmacy, University of Szeged, Hungary
György Grosz
; MDE GmbH, Walldorf, Germany
Miklós Süle
; MDE GmbH, Walldorf, Germany
Anikó Nagy
; Heim Pál Children’s Hospital, Budapest, Hungary
Zita Tiszai
; Department of Pharmacodynamics and Biopharmacy, University of Szeged, Hungary
Reza Samavati
; Department of Pharmacodynamics and Biopharmacy, University of Szeged, Hungary
Róbert Gáspár
; Department of Pharmacodynamics and Biopharmacy, University of Szeged, Hungary
Abstract
Aim To develop an electromyography method for pregnant
rat uterus in vivo and to separate myometrial signals
from the gastrointestinal tract signals.
Methods: Pregnant Sprague-Dawley rats (n = 8) were anaesthetized
and their stomach, small intestine, and large intestine
were removed from the abdomen. A pair of thread
electrodes was inserted into the uterus, while a pair of disk
electrodes was placed subcutaneously above the myometrium.
Additionally, a strain gauge sensor was fixed on the
surface of the myometrium and cecum for the parallel detection
of mechanical contractions in rats (n = 18) with intact
gastrointestinal tract. The filtered electric signals were
amplified and recorded by an online computer system and
analyzed by fast Fourier transformation. The frequency of
the electric activity was characterized by cycle per minute
(cpm), the magnitude of the activity was described as
power spectrum density maximum (PsDmax).
Results: The frequency of the pregnant uterine activity
was 1-3 cpm, which falls within the same range as that of
cecum. Measuring by both electrodes, oxytocin (1 μg/kg)
increased and terbutaline (50 μg/kg) decreased the PsDmax
by 25%-50% (P < 0.001) and 25%-40% (P < 0.01), respectively.
We found a strong positive correlation between the
alterations of PsDmax values and the strain gauge sensordetected
mechanical contractions (area under curve). The
GI specific compounds (neostigmine, atropine) mainly affected
the cecal activity, while myometrium specific drugs
(oxytocin, terbutaline) influenced the myometrial signals
only.
Conclusion: Our method proved to be able to detect the
myoelectric activity that reflects the mechanical contraction.
The overlapping myometrial and cecal signals are not
separable, but they can be distinguished based on the
much higher activity and different pharmacological reactivity
of the pregnant uterus. Thus, the early signs of contractions
can be detected and labor may be predicted in a
fast and sensitive way.
Keywords
Hrčak ID:
181596
URI
Publication date:
15.4.2017.
Visits: 1.339 *