Tyrosine kinase A, galanin and nitric oxide synthase within basal forebrain neurons in the rat

• Published in: Neuroscience 1998-11, Vol.87 (2), p.447-461
• Main Authors: Sobreviela, T, Jaffar, S, Mufson, E.J
• Format: Article
• Language: English
• Subjects: Anatomy; Animals; Biological and medical sciences; Central nervous system; cholinergic; co-localization; Fundamental and applied biological sciences. Psychology; Galanin - metabolism; Immunohistochemistry; Male; NADPH Dehydrogenase - metabolism; nerve growth factor; Neurons - enzymology; neuropeptide; Nitric Oxide Synthase - biosynthesis; Nitric Oxide Synthase Type I; Prosencephalon - cytology; Prosencephalon - enzymology; Proto-Oncogene Proteins - metabolism; Rats; Rats, Sprague-Dawley; receptor; Receptor Protein-Tyrosine Kinases - metabolism; Receptor, trkA; Receptors, Nerve Growth Factor - metabolism; tyrosine kinase; Vertebrates: nervous system and sense organs
• ISSN: 0306-4522; 1873-7544
• DOI: 10.1016/S0306-4522(98)00153-5

Cholinergic basal forebrain neurons appear to play a key role in cognition and attention. In rat, basal forebrain neurons express multiple proteins including the high-affinity signal transducing tyrosine kinase A receptor for nerve growth factor, the neuropeptide galanin and nitric oxide synthase, a marker for the novel neurotransmitter nitric oxide. The present study was undertaken to define the relationship between neurons expressing each of these markers within the medial septum-vertical limb of the diagonal band, horizontal limb of the diagonal band and nucleus basalis in colchicine pre-treated rats. Tyrosine kinase A-immunopositive neurons were seen throughout all subfields of the basal forebrain. In contrast, nitric oxide synthase- and galanin-immunoreactive neurons were mainly distributed within the septal-diagonal band complex. Co-localization experiments revealed that virtually all nitric oxide synthase-positive neurons (visualized by nicotinamide adenine dinucleotide phosphate-diaphorase histochemistry) also contained tyrosine kinase A, whereas, many fewer tyrosine kinase A neurons were nicotinamide adenine dinucleotide phosphate-diaphorase positive within the medial septum-vertical limb of the diagonal band. Within the horizontal limb of the diagonal band, numerous nicotinamide adenine dinucleotide phosphate-diaphorase neurons expressed tyrosine kinase A, whereas only a small number of tyrosine kinase A neurons contained nicotinamide adenine dinucleotide phosphate-diaphorase. Within the nucleus basalis very few neurons were nicotinamide adenine dinucleotide phosphate-diaphorase reactive, and a minor number contained tyrosine kinase A. Additional co-localization experiments revealed minor percentages of neurons containing nicotinamide adenine dinucleotide phosphate-diaphorase and galanin immunoreactivity within the various subfields of the basal forebrain. Within the horizontal limb of the diagonal band minor numbers of nicotinamide adenine dinucleotide phosphate-diaphorase-reactive perikarya displayed galanin. Similarly, only a few galanin-containing neurons expressed nicotinamide adenine dinucleotide phosphate-diaphorase. The existence of tyrosine kinase A, nitric oxide synthase and galanin within select neuronal subgroups of the cholinergic basal forebrain suggests that these perikarya are responsive to a complex set of chemical signals. A greater understanding of the chemical signature of the cholinergic basal forebrain neurons will provide t