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Norepinephrine Inhibits Vasopressin‐Stimulated Flank Marking in the Syrian Hamster by Acting Within the Medial Preoptic‐Anterior Hypothalamus
Author(s) -
Whitman D. Carol,
Hennessey Ann C.,
Albers H. Elliott
Publication year - 1992
Publication title -
journal of neuroendocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.062
H-Index - 116
eISSN - 1365-2826
pISSN - 0953-8194
DOI - 10.1111/j.1365-2826.1992.tb00202.x
Subject(s) - flank , vasopressin , endocrinology , medicine , microinjection , hypothalamus , estrous cycle , dopamine , hamster , norepinephrine , biology , chemistry , anatomy
Syrian hamsters exhibit a form of scent marking behavior called flank marking. Flank marking, which is elicited during social contact with other hamsters and by the odors of other hamsters, communicates socially important information such as mate choice and dominance status. Vasopressinergic activity within the medial preoptic‐anterior hypothalamic continuum (MPOA‐AH) is essential for the expression of flank marking. In female hamsters, an inverse relationship exists between the expression of flank marking and sexual receptivity during the 4‐day estrous cycle. Since norepinephrine (NE) appears to facilitate sexual receptivity, the present study investigated whether NE might have an inhibitory effect on flank marking by acting on Vasopressinergic activity within the MPOA‐AH. Microinjection of 9.0 μM arginine vasopressin (AVP) into the MPOA‐AH stimulated high levels of flank marking. Microinjection of 9.0 μM AVP combined with NE in concentrations of 4.0, 0.4 or 0.2 nM, drastically reduced or eliminated flank marking. In contrast, AVP in combination with 0.09, 0.04 or 0.004 nM NE produced no significant reductions in flank marking. In addition, microinjection of 9.0 μM AVP, in combination with epinephrine (4.0 nM), but not dopamine (4.0 nM), serotonin (4.0 nM) or neuropeptide Y (900 μM), significantly reduced AVP‐induced flank marking. In male hamsters, microinjection of NE (4.0 nM) combined with AVP (9.0 μM) into the MPOA‐AH was not found to inhibit AVP‐stimulated flank marking. These results suggest that NE is involved in regulating the expression of flank marking during the estrous cycle by acting on Vasopressinergic activity within the MPOA‐AH.