Contribution of the supra-optic nucleus to brain and pituitary pools of immunoreactive vasopressin and particular opioid peptides, and the interrelationships between these, in the rat.
Discrete, bilateral, radiofrequency destruction of the supra-optic nucleus resulted in a parallel fall in levels of immunoreactive (ir) dynorphin (DYN), ir-alpha-neo-endorphin (alpha-NE) and ir-vasopressin (VP) in the hypothalamus, neurointermediate lobe (NIL) of the pituitary and septum of rats, whereas in the medulla/pons, midbrain and anterior lobe (AL), levels of theses peptides were not significantly changed. The content of ir-beta-endorphin (beta-endorphin (beta-EP) was, in contrast, elevated in the hypothalamus and unchanged in the NIL and AL, while that of ir-met-enkephalin (ME) was modified in neither the hypothalamus nor medulla/pons. As evaluated in lesioned and sham rats, collectively, hypothalamic levels of ir-DYN, ir-alpha-NE and ir-vP were positively correlated with their counterparts in the NIL but not, with the exception of ir-VP, with those in the AL. Ir-beta-E did not show these relationships. Within the NIL and in the hypothalamus, levels of ir-DYN, ir-alpha-NE and ir-VP were positively correlated with each other and independent of those of ir-beta-EP and ir-ME. In the ALK and other brain tissues, however, only those of ir-DYN and ir-alpha-NE were positively and significantly correlated in contrast to ir-VP. Further, across all structures, although the ratio of levels of ir-alpha-NE to ir-DYN was quite constant, that of ir-VP to ir-DYN varied enormously. These data indicate that: (1) the supra-optic nucleus may contribute to NIL, hypothalamic and septal but not to AL, midbrain or medulla/pons pools of ir-VP, ir-DYN and ir-alpha-NE, and that it interacts with those of ir-beta-EP in the hypothalamus. (2) in the NIL and hypothalamus, ir-DYN, ir-alpha-NE and ir-VP are, as compared to ir-beta-EP and ir-ME, closely interrelated. (3) AL pools of DYN and ir-alpha-NE are closely coupled but, in contrast to NIL pools, not related to ir-VP and independent of the hypothalamus. (4) Extrahypothalamic brain pools of ir-DYN and ir-alpha-NE may be not related to ir-VP. The possible existence of ir-DYN and ir-alpha-NE independently or ir-vP in the AL and extrahypothalamic nervous tissue is discussed.
D000818:Animals; D001923:Brain Chemistry; D004399:Dynorphins; D004723:Endorphins / Q000032:analysis*; D008297:Male; D010286:Paraventricular Hypothalamic Nucleus / Q000502:physiology; D010902:Pituitary Gland / Q000032:analysis*; D051381:Rats; D011919:Rats, Inbred Strains; D013495:Supraoptic Nucleus / Q000502:physiology*; D014667:Vasopressins / Q000032:analysis*
D004723:Endorphins; D014667:Vasopressins; D004399:Dynorphins