frequency yawning: A behavioural event of
Chakradhara Rao US, Suresh Kumar S.
Department of Pediatric
Haematology and Oncology, University Hospitals
of Geneva, Geneva, Switzerland
Department of Pharmacology,
JIPMER, Pondicherry, India
Ethanol withdrawal (EW) symptoms occur due
to sudden decrease in intake of alcohol
following repeated exposure to high doses. It
ranges from anxiety, tremors and autonomic
overactivity to delirium and seizures. EW is
studied in animals by scoring rigidity, tremors
and irritability. Altered central
neurotransmitter activity is attributed in
occurrence of EW .
Yawning also occurs in animals and humans
due to altered central neurotransmitter
activity. It is facilitated by glutamate and
dopamine agonists  and is frequently
seen with opioid withdrawal.
Yawning is also observed in mild alcohol
withdrawal in rats . This observation
is further supported by a recent study which has
shown that alcohol alters dynorphins and
nociception pathways in the brain which also
shares the yawning inducing pathways
. However, yawning occurs less
frequently in neonatal ethanol withdrawal
compared to narcotic withdrawal
Yawning induced by cholinergic and
dopaminergic agents, is inhibited by
cannabinoids, and is also seen during withdrawal
of cannabinoids . Similarly yawning
induced by apomorphine is inhibited by ethanol
at high doses in rats . This suggests
the possibility of stimulation of yawning during
withdrawal due to loss of inhibition by
Thus, we hypothesize that increased
frequency of yawning observed in EW may be due
to altered central neurotransmitters. Clinically
yawning may be considered as a reflex originated
from increased craving for ethanol and may be
considered as one of the behavioural events used
to assess the effect of drugs in EW.
 E. Tupala and Tiihnonen,
Dopamine and alcoholism: neurobiological basis
of ethanol abuse. Prog Neuropsychopharmacol Biol
Psychiatry, 28 (2004), pp.
 U.S. Rao Chakradhara and K.S.
Karanth, Dextromethorphan attenuates ethanol
withdrawal induced hyperalgesia in rats. Int J
Pharmacol, 5 (2009), pp. 327&endash;332.
 D'Addario C, Caputi FF,
Rimondini R, Gandolfi O, Del Borrello E,
Candeletti S, Romualdi P. Different alcohol
exposures induce selective alterations on the
expression of dynorphin and nociception systems
related genes in rat brain. Addict Biol. 2011.