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Effects of hypocretin‐1 in 192‐IgG–saporin‐lesioned rats
Author(s) -
BlancoCenturion Carlos A.,
Shiromani Anjelica,
Winston Elizabeth,
Shiromani Priyattam J.
Publication year - 2006
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/j.1460-9568.2006.05074.x
Subject(s) - basal forebrain , cholinergic neuron , orexin , forebrain , saporin , cholinergic , lateral hypothalamus , endocrinology , neuroscience , neuropeptide , arousal , medicine , cataplexy , narcolepsy , hypothalamus , biology , central nervous system , receptor , immunotoxin , antibody , neurology , immunology , monoclonal antibody
Hypocretin, also known as orexin, is a neuropeptide located in the perifornical region of the lateral hypothalamus; this region projects to all the major arousal centres including the basal forebrain. The basal forebrain contains a mixed population of neurons, some of which are cholinergic. To identify the relative contribution of the noncholinergic neurons to arousal, here we utilized 192‐IgG–saporin to lesion the basal forebrain cholinergic neurons and determine whether microinjection of hypocretin‐1 to the basal forebrain is still effective in inducing arousal. In Sprague–Dawley rats given 192‐IgG–saporin (intraventricular, 6 µg; n = 7) 92% of the basal forebrain cholinergic neurons were destroyed compared to nonlesioned rats ( n = 5). In the lesioned rats microinjection of hypocretin‐1 (0.0625, 0.125 or 0.25 nmol in 250 nL) to the basal forebrain increased waking and suppressed sleep (both non‐REM and REM) in a concentration‐dependent manner and to the same extent as in nonlesioned rats. These results suggest that, in the absence of the basal forebrain cholinergic neurons, the basal forebrain noncholinergic neurons are able to convey hypocretin's arousal signal unabated.