ISSN:
1432-0878
Keywords:
Retina
;
Hypothalamus (Mammals)
;
Suprachiasmatic nucleus
;
Neuroendocrinology
;
Autoradiography
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary Retino-hypothalamic connections have been studied autoradiographically in the rat, guinea pig, rabbit, cat and monkey following the intravitreal injection of 3H-leucine or 3H-proline, and electron microscopically following unilateral eye removal in the guinea pig and monkey. In each of the species examined evidence has been found for a direct projection from the retina to the suprachiasmatic nucleus, but to no other region of the hypothalamus. The projection to the suprachiasmatic nucleus is always bilateral (even in the albino guinea pig, in which all other components of the retinal projection are crossed) but from grain counts in our autoradiographs it appears that the input to the contralateral nucleus is about twice as heavy as that on the ipsilateral side. Most of the retinal fibers appear to terminate within the ventral part of the nucleus where they form asymmetric synapses either upon small dendritic branches or dendritic spines. The possible role of this retinal projection to the suprachiasmatic nucleus in mediating a variety of light-induced neuroendocrine responses is discussed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00307084
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