Norepinephrine content in discrete brain areas and neurohypophysial vasopressin in rats after a 9-d spaceflight (SLS-1).
The norepinephrine (NE) content in discrete brain areas and the vasopressin content in the neurohypophysial system were assessed in rats after a 9-d spaceflight and after a recovery period (9 d). The NE content in the locus coeruleus decreased significantly in spaceflight rats (2.9 +/- 0.3 vs. 8.9 +/- 0.7 pmol.structure-1 for control rats, p < 0.001), but showed no difference between control and flight animals after a 9-d recovery. These findings were probably due to an acute stress undergone during landing. The NE content was unchanged in the A2 and A5 cell groups. In rats flown aboard SLS-1, the vasopressin content was increased in the posterior pituitary (1.47 +/- 0.1 vs. 0.86 +/- 0.1 micrograms.structure-1, for control rats, p < 0.01), and was significantly decreased in the hypothalamus (8.95 +/- 2.0 vs. 17.6 +/- 2.2 ng.structure-1, for control rats, p < 0.05). We conclude that the NE depletion in the locus coeruleus and the alteration in vasopressin release were consistent with an acute stress, likely occurring during and/or after landing. These changes tend to mask the actual neuroendocrine modifications caused by microgravity.
Fareh
J
J
Laboratoire de Physiologie de l'Environment, URA 1196 CNRS-Fac. Med. Lyon Grange-Blanche, France.
Cottet-Emard
J M
JM
Pequignot
J M
JM
Jahns
G
G
Meylor
J
J
Viso
M
M
Vassaux
D
D
Gauquelin
G
G
Gharib
C
C
D000818:Animals; D006112:Gravitation; D007031:Hypothalamus / Q000737:chemistry*; D008125:Locus Coeruleus / Q000737:chemistry*; D009638:Norepinephrine / Q000032:analysis* / Q000172:deficiency; D010904:Pituitary Gland, Posterior / Q000737:chemistry*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013026:Space Flight; D013312:Stress, Physiological / Q000503:physiopathology; D013997:Time Factors; D014667:Vasopressins / Q000032:analysis*
D014667:Vasopressins; D009638:Norepinephrine