| Abstract: | The rat hypothalamus has the capacity to bind alpha-bungarotoxin with high affinity to a saturable number of non-interacting receptors with a pharmacologic profile consistent with a nicotinic receptor. Studies of the hypothalamic nuclear distribution of cholinergic receptors showed no specific pattern of enrichment of muscarinic receptors. In contrast, there was a distinct distribution of nicotinic receptors with high concentrations in the suprachiasmatic, dorsomedial and preoptic suprachiasmatic nuclei. Thus, the quantitative distribution of nicotinic receptors in hypothalamic nuclei is in general agreement with the observed autoradiographic distribution of radioactive alpha bungarotoxin. Further, these results confirm the existence of high concentrations of nicotinic receptors in hypothalamic regions of the rat implicated in neuroendocrine function. |
