Affiliation:
1. Department of Zoology, University of Lucknow, Lucknow, Uttar Pradesh 226007, India
2. Ancient DNA Lab, Birbal Sahni Institute of Palaeosciences, Lucknow, Uttar Pradesh 226007, India
Abstract
The molecular regulation of sleep in avian migrants is still obscure. We thus investigated this in migratory redheaded buntings, where four life-history states (LHS; i.e. non-migratory, pre-migratory, migratory and refractory states) were induced. There was increased night-time activity (i.e.
Zugunruhe
) during the migratory state with reduced daytime activity. The recordings of the sleep–wake cycle in buntings showed increased night-time active wakefulness coupled with drastically reduced front and back sleep during migratory phase. Interestingly, we found the buntings to feed and drink even after lights-off during migration. Gene expression studies revealed increased hypothalamic expression of glucocorticoid receptor (
nr3c1
), and pro-inflammatory cytokines (
il1b
and
il6
) in pre-migratory and migratory states, respectively, whereas in brainstem Ca
2+
/calmodulin-dependent protein kinase 2 (
camk2
) was upregulated during the migratory state. This suggested a heightened pro-inflammatory state during migration which is a feature of chronic sleep loss, and a possible role of Ca
2+
signalling in promoting wakefulness. In both the hypothalamus and brainstem, the expression of melatonin receptors (
mel1a
and
mel1b
) was increased in the pre-migratory state, and growth hormone-releasing hormone (
ghrh
, known to induce sleep) was reduced during the migratory state. The current results demonstrate key molecules involved in the regulation of sleep–wake cycle across LHS in migratory songbirds.
Funder
Science and Engineering Research Board
R&D
Subject
General Agricultural and Biological Sciences,General Environmental Science,General Immunology and Microbiology,General Biochemistry, Genetics and Molecular Biology,General Medicine
Cited by
1 articles.
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