INTERACTIONS OF QUININE AND SEROTONERGIC AGENTS IN PENTOBARBITONE - INDUCED SLEEP IN RATS
INTERACTIONS OF QUININE AND SEROTONERGIC AGENTS IN PENTOBARBITONE - INDUCED SLEEP IN RATS
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Date
1994-04
Authors
MODUPE, BADEJOGBIN OLUYOMI
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Abstract
The interactions between quinine serutuninergic agents on
the EEG, EMG changes and behavioural sleep induced by
pentobarbitone were studied in rats. All drugs were injected
i ntr aper i tonealy.
The sedative-hypnotic effect of pentobarbitone (5-30mg./kg)
was found to be dependent on dose, with hypnosis being attained
by the higher dose range (15-30mg/kg) . High dose (25mg/kg) of
pentobarbitone synchronised the F C O C and BSRF of the control
EEG in the slow wave sleep (SW3) stage with particular
depression of the RF arid the EMG.
When administered singly and in high doses (12-64mg/kg),
5- hydroxytryptophan (5-HTP) and quinine (5-50mg/kg)
respectively showed sedative effects that were dose- dependent.
High dose (20mg/kg) of Quinine sychronised the resting EEG and
Initially briefly stimulated, though eventually predominantly
depressed the EMG, suggesting a mechanism similar to that of
the general CNS depressants. Low dose (0.1mg/kg) of quinine
did not sedate but activated the entire resting state or
control EEG and EMG. These were evident as faster, lower
amplitude, asynchronous, mixed frequencies voltages and
slightly increased multiple motor-unit voltages respectively.
On sleep induced by pentobarbitone,5-Hydroxytryptophan
5-HTP (8-32mg/kg) and high doses (20-50mg/kg) of quinine
respectively caused a potentiation that was marked by prolonged
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duration uT pentobarbitone-induced bleep. On the EEG and EMG
patterns under pentobarbitone (25mg/kg), quinine 20mg/kg
Increased the wave amplitude of the FC and OC with profound
slowing of the BSRF and further reduction of muscle activity
(muscle relaxation). Low doses (0.05 and 0.1 rug/kg) of quinine
delayed the onset of sleep induced by pentobarbitone by 64% and
36% and shortened the duration respectively by 23% and 20%, the
EEG arid EMG activities were also activited.
A high dose (25mg/kg) of quinine potentiated 5-HTP-induced
prolongation of pentobarbitone sleep by 23% while low dose
(0.05mg/kg) of quinine decreased it by 40%.
P-Chlorophenylalanine ((PCPA), 300mg/ky) reduced the
duration of pentobarbitone sleep and antagonised the
potentiation of pentobarbitone sleep by quinine.
Ketanserin (2.5mg/kg) not only potentiated pentobarbitone
sleep but enhanced significantly the potentiation of
pentobarbitone sleep by 5-HTP (16mg/kg) as well as by quinine
(25mg/kg).
Methysergide (8mg/kg), an antagonist of both 5-HT1 , and 5-
HT; receptors and a partial agonist of 5-HT, receptor partially
antagonised the potentiating effect of high dose of quinine on
pentobarbitone sleep.
The present data show that depending on the dose, quinine
has both excitatory and inhibitory effects on the state of
condousness and that serotoninergic mechanism(s) may under the
its effect on the state of sleep in rats.
Description
A Thesis Submitted to the Postgraduate School, Ahmadu
University, Zaria, in partial fulfilment of the
Requirements for the degree of MASTER OF SCIENCE.
Keywords
INTERACTIONS, QUININE, SEROTONERGIC, AGENTS, PENTOBARBITONE, INDUCED, SLEEP, RATS