Argyrophilic dark neurons distribute with a different pattern in the brain after over hours treadmill running and swimming in the rat.
Argyrophil III staining is a useful method for the detection of dark neurons (DNs) that would reflect an early cytopathic feature. We examined the appearance of DNs following the stressful exercises (0.5-3 h swimming in a pool of 25-45 cm depth; 1-2 h running on a treadmill at the speed of 600-1200 cm/min) in the rat. After the swimming, DNs were detected in the hippocampus (CA1-2 pyramidal cell layer, oriens layer), somatosensory cortex, entorhinal cortex, hypothalamus, habenular nucleus, amygdaloid nucleus, striatum, accumbens and sometimes in lateral septal nucleus. After the running, DNs appeared in the visual cortex, deepest layer of area 17 and 18a, motor cortex, red nucleus, somatosensory cortex, entorhinal cortex, and hippocampus (dentate gyrus). Thus, the DNs appeared mainly in the limbic structure after the swimming, and in the limbic structure, motor-related regions and visual cortex after the running. Further, the number of the DNs and the extent of area where they distributed were dependent on the strength and the duration of the exercises. In hematoxylin-eosin (H-E) staining, we often detected pycnotic cells (dark stained soma) in CA1 hippocampus where argyrophil positive cells were most abundant. The picnotic cells were not so common in other areas. Data suggest that DNs are induced by stressful exercises. They might reflect an early cell injury following stress and overexcitation.
Ishida
K
K
Department of Physiology, Nagoya City University Medical School, Nagoya, Japan. ishida@met.nagoya-u.ac.jp
Ungusparkorn
C
C
Hida
H
H
Aihara
N
N
Ida
K
K
Nishino
H
H
D000818:Animals; D001921:Brain / Q000473:pathology*; D006624:Hippocampus / Q000473:pathology; D008297:Male; D009043:Motor Activity / Q000502:physiology*; D009474:Neurons / Q000473:pathology*; D051381:Rats; D017208:Rats, Wistar; D012834:Silver; D013194:Staining and Labeling; D013312:Stress, Physiological / Q000209:etiology / Q000473:pathology; D013550:Swimming / Q000502:physiology
D012834:Silver