Biological Properties of the Nerve Growth Factor
While during early developmental stages, both sensory and sympathetic nerve cells are receptive to the Nerve Growth Factor (NGF) only the sympathetic neurons retain this prerogative at later stages and in adult life. These differences between the two types of nerve cells, already apparent from earlier studies by Levi-Montalcini in chick embryo, become more evident when the NGF effect is studied in newborn and adult mice. Neither in newborn nor in adult mouse does NGF elicit an overgrowth of sensory ganglia; the sympathetic ganglia, on the contrary, undergo a dramatic increase in size (3, 5). When highly purified NGF, the NGF molecule whose primary structure has been established, is injected in newborn mice or rats at a dose of 10 μg/g body weight, a progressive enlargement of all sympathetic ganglia ensues. The size usually reaches 4–5 fold the normal values after a week or ten days treatment (Fig. 1). Even more dramatic overgrowth can be obtained by using larger doses of NGF for longer periods of time (4). From histological examination the size increase of each ganglion appears to be due to both an increase in cell number and to an increase in cell size (Fig. 2). Therefore, mitotic activity, as determined between the third and ninth day after birth, is considerably increased in NGF-treated mice and rats.
KeywordsNerve Growth Factor Tyrosine Hydroxylase Microsomal Fraction Sympathetic Ganglion Receptive Nerve Cell
Unable to display preview. Download preview PDF.
- 1.Bucker, E.D., Schenkein, I. and Bone, J.L., Cancer Res., 20 (1960) 1220.Google Scholar
- 3.Levi-Montalcini, R., Harvey Lecture Sci., 60 (1966) 217.Google Scholar
- 4.Levi-Montalcini, R. and Angeletti, P.U., Physiol. Rev., 48 (1968) 534.Google Scholar
- 6.Moore, B.W. and Perez, V.J., J. Immun., 96 (1966) 1000.Google Scholar
- 8.Wasserman, E. and Levine, L., J. Immun., 87 (1961) 290.Google Scholar