Histamine-immunostaining in the rat median eminence: an unexpected form of cross-reactivity with LH-RH.
By use of two antisera (alpha HA-1, alpha HA-2) raised to histamine (HA) a similar distribution of HA-positive cell bodies and fibres in the rat brain has been demonstrated, except for a dense plexus in the median eminence which was only found with alpha HA-1. The HA-immunostaining in the median eminence was similar in distribution to that of luteinizing hormone-releasing hormone (LH-RH). In gelatin models containing LH-RH a concentration-dependent increase in immunofluorescence intensity (range: 0.01-10 microM) was found with alpha HA-1 but not with alpha HA-2. To evaluate the significance of the cross-reaction of alpha HA-1 with LH-RH, antero- or postero-lateral deafferentations of the rat mediobasal hypothalamus were made to discriminate between LH-RH and HA projections to the median eminence. The LH-RH- and HA-immunostaining in the median eminence was not affected by posterolateral deafferentations but was abolished in rats with an anterolateral lesion. We conclude that the HA-immunostaining in the rat median eminence is due to a cross-reaction of alpha HA-1 with LH-RH.
D000818:Animals; D003429:Cross Reactions; D005455:Fluorescent Antibody Technique; D007987:Gonadotropin-Releasing Hormone / Q000032:analysis / Q000276:immunology*; D006632:Histamine / Q000032:analysis / Q000276:immunology*; D007106:Immune Sera / Q000276:immunology; D008297:Male; D008473:Median Eminence / Q000032:analysis*; D051381:Rats; D011919:Rats, Inbred Strains; D011969:Receptors, Histamine H1 / Q000276:immunology; D011970:Receptors, Histamine H2 / Q000276:immunology
D007106:Immune Sera; D011969:Receptors, Histamine H1; D011970:Receptors, Histamine H2; D007987:Gonadotropin-Releasing Hormone; D006632:Histamine