A sex comparison of serotonin immunoreactivity and content in the ferret preoptic area/anterior hypothalamus.
Previous studies with rats raised the possibility that sexually dimorphic features of the medial preoptic area/anterior hypothalamus (POA/AH) may result, in part, from a sex difference in the serotonergic innervation of this region. We asked whether a similar phenomenon may occur in a carnivore, the ferret. A sexually dimorphic male nucleus of the dorsal POA/AH (Mn-POA/AH) has previously been characterized in Nissl-stained sections of the male ferret forebrain; this nucleus is absent in females. A nondimorphic ventral nucleus of the POA/AH is found in both sexes. In the present study numerous serotonin (5-HT) immunoreactive (ir) fibers were observed in the dorsal POA/AH of gonadectomized adult ferrets of both sexes. By contrast, in both sexes the ventral nucleus of the POA/AH had many fewer 5-HTir fibers. A similar difference in the distribution of immunoreactivity between dorsal and ventral POA/AH was observed for tyrosine hydroxylase (TH) localized in cell bodies and in nerve fibers and for H222ir estrogen receptors localized in cell nuclei. Likewise, in both sexes the content of 5-HT and dopamine (DA), measured by high pressure liquid chromatography with electrochemical detection, were significantly higher in the dorsal than the ventral POA/AH, thereby corroborating observed regional differences in 5-HTir and THir fibers, respectively. The present findings provide no support for the notion that sexually dimorphic cytoarchitectonic features of the dorsal POA/AH in ferrets are associated with a sex difference in the serotonergic innervation of this region.
Baum
M J
MJ
Department of Biology, Boston University, MA 02215.
Tobet
S A
SA
D015102:3,4-Dihydroxyphenylacetic Acid / Q000032:analysis; D000818:Animals; D004298:Dopamine / Q000032:analysis; D005260:Female; D005289:Ferrets / Q000378:metabolism*; D007032:Hypothalamus, Anterior / Q000737:chemistry*; D008297:Male; D011301:Preoptic Area / Q000737:chemistry*; D012701:Serotonin / Q000032:analysis*; D012727:Sex Characteristics
D015102:3,4-Dihydroxyphenylacetic Acid; D012701:Serotonin; D004298:Dopamine