Permanent alteration of peptide feedback on dopamine neurons after injection of α-melanotropin antiserum at a critical period of postnatal development

Activation of Tuberoinfundibular but Not Tuberohypophysial Dopaminergic Neurons following Intracerebroventricular Administration of Alpha-Melanocyte-Stimulating Hormone

“…Lichtensteiger and Lienhart [9], Lichtensteiger and Monnet [10] and Lichtensteiger and Schlumpf [11] suggested that the increase in intensity of catecholamine fluorescence in the ar cuate nucleus after aMSH administration was due to activation of DA neurons. The present study, using techniques that differ entiate between tuberoinfundibular and tuberohypophysial DA neurons, extends these results by demonstrating that aMSH in creases tuberoinfundibular but not tuberohypophysial DA neuronal activity.…”

“…The effect of ct-melanocyte-stimulating hormone («MSH) on the activity of different central dopaminergic neurons in the male rat was determined by measuring the concentration of 3,4-dihydroxyphenylacetic acid (DOPAC) and the accumulation of 3,4-dihydroxyphenylalanine (DOPA) following the administration of a decarboxylase inhibitor in brain regions that contain termi nals of nigrostriatal (striatum), mesolimbic (nucleus accumbens), tuberoinfundibular (median eminence) and tuberohypophysial Lichtensteiger and Lienhart [9], Lichtensteiger and Monnet [10] and Lichtensteiger and Schlumpf [11] reported that aMSH administration increased the intensity of catecholamine fluores cence in the arcuate nucleus and concluded that this increase in fluorescence intensity was due to activation of dopamine (DA) neurons. The arcuate nucleus contains the perikarya of two dif ferent DA neuronal systems: tuberoinfundibular and tubero hypophysial DA neurons [12].…”