Differential effects of colchicine on central dopaminergic neuronal activity and prolactin secretion in estrogen-primed ovariectomized rats.
Colchicine is a potent chemical that disrupts the assembly of microtubulin and affects the integrity of cytoskeleton. It is commonly used to block the axonal transport in neurons. Central administration of colchicine (48 microg/3 microl/rat) two days earlier significantly lowered 3,4-dihydroxyphenylacetic acid (DOPAC) levels in the striatum and nucleus accumbens, both in the morning and in the afternoon. Median eminence DOPAC levels exhibit a diurnal change between morning and afternoon as previously shown. Colchicine treatment lowered and elevated median eminence DOPAC levels in the morning and afternoon, respectively. The estrogen-induced prolactin surge was also blocked. The findings indicate that neuronal inputs are necessary for maintaining basal activities in all dopaminergic neurons, while an inhibitory one predominates in the afternoon for TIDA neurons.
Yang
Shu-Chuan
SC
Department of Physiology, School of Medicine, National Yang-Ming University, Taipei, Taiwan, ROC.
Pan
Jenn-Tser
JT
D015102:3,4-Dihydroxyphenylacetic Acid / Q000378:metabolism; D000818:Animals; D002940:Circadian Rhythm / Q000187:drug effects / Q000502:physiology; D003078:Colchicine / Q000494:pharmacology*; D003342:Corpus Striatum / Q000166:cytology / Q000187:drug effects; D004298:Dopamine / Q000502:physiology*; D004967:Estrogens / Q000494:pharmacology; D005260:Female; D008473:Median Eminence / Q000166:cytology / Q000187:drug effects; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D009714:Nucleus Accumbens / Q000166:cytology / Q000187:drug effects; D010052:Ovariectomy; D011388:Prolactin / Q000097:blood / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
D004967:Estrogens; D015102:3,4-Dihydroxyphenylacetic Acid; D011388:Prolactin; D003078:Colchicine; D004298:Dopamine