An HRP study on cell types and their regional topography within the locus coeruleus innervating the supraoptic nucleus of the rat.
Detailed histochemical studies have been performed on the distribution of various types of horseradish peroxidase (HRP) labeled neurons in the rat dorsal pons with special reference to regional topography within the locus coeruleus (LC) after HRP injections into the nucleus supraopticus (SO). Successful HRP injections into the SO resulted in labeling only in the ipsilateral LC but not in the other structures of the pons. In these cases a few densely labeled multipolar neurons were scattered in both dorsal and ventral divisions throughout the LC. HRP deposition in the hippocampus proper increased significantly the number of labeled neurons in the dorsal division of the ipsilateral LC where a few fusiform neurons in addition to more numerous multipolar ones were labeled. These results strongly suggest that the LC must be the only site of the dorsal pons that innervates the SO, that mainly a part of multipolar neurons may project to the ipsilateral SO, and that regional topography within the LC innervating the SO must be very different from that innervating the hypothalamus. At the present time there remains a possibility that the LC may project to the contralateral SO.
D000818:Animals; D005260:Female; D006624:Hippocampus / Q000166:cytology; D006735:Horseradish Peroxidase; D007031:Hypothalamus / Q000166:cytology*; D008125:Locus Coeruleus / Q000166:cytology*; D009434:Neural Pathways; D009476:Neurons, Efferent / Q000166:cytology*; D011149:Pons / Q000166:cytology; D051381:Rats; D013495:Supraoptic Nucleus / Q000166:cytology*
D006735:Horseradish Peroxidase