Study type: Medical/biological study (experimental study)

A comparison between microwave irradiation and decapitation: basal levels of dynorphin and enkephalin and the effect of chronic morphine treatment on dynorphin peptides. med./bio.

Published in: Neuropeptides 1997; 31 (4): 357-365

Aim of study (acc. to author)

To analyse opioid peptides in tissue extracts of various brain structures and the pituitary gland from rats sacrificed by microwave irradiation, and to compare with peptide levels from decapitated rats.

Background/further details

Additionally, effects of morphine treatment on prodynorphin peptide levels were examined and compared with previous data in decapitated rats.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 2.45 GHz
Exposure duration: 2 s

General information

small tube for head, large tube for rest of body s.a.( Nordberg et al. 1977)

Exposure 1

Main characteristics
Frequency 2.45 GHz
Type
Exposure duration 2 s
Exposure setup
Parameters
Measurand Value Type Method Mass Remarks
power 5 kW maximum - - -

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Investigated organ system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

Levels of dynorphin A and B were consistently higher in extracts from microwave-exposed rats, whereas in these extracts immunoreactive levels of Leu-enkephalin Arg6, an endogenous metabolite of dynorphin peptides, were either lower than, the same as or higher than in decapitated animals. Immunoreactive levels of Met-enkephalin Arg6Phe7 were higher in microwave-exposed animals.
Dynorphin immunoreactive levels were higher in the nucleus accumbens and striatum of morphine-tolerant animals than in corresponding areas in saline-treated rats.
These findings indicate tissue-specific metabolism of prodynorphin peptides. They show that metabolism of opioid peptides occurs during the dissection procedure after decapitation of the rat even though precautions were taken to minimize degradation.

Study character:

Study funded by