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A histamine H2 receptor antagonist blocks the suppressive vasopressin response to fear-related emotional stress
S169
EFFECTS
OF THE MIDBRAIN
HYPOTHALAMIC LEVELS
RAPHE
NUCLEUS
PARAVENTRICULAR
IN CATS.
STIMULATION
NUCLEUS
TOSHIMASA
ml,
ON SEROTONIN
AND ON PLASMA OSAKAl.
RELEASE
VASOPRESSIN
IN THE
AND OXYTOCIN
KEN’ICHI YAMAGUCm2,
TAKASHI
HIGUCH13, HIDE0 NEGOR03 AND HIROSHI YAh4ASHIT~1, lJ&ot. of avsiol.. Univ. of Occup and Environ. Health. Kitakvushu 8a2Deot. of Phvsiol.. Sch. of Med.. NiiPata Univ.. Niiaata 950. & 3Deot. of Phvsiol.. Fukui Med. Sch.. Fukui 910-11. Jam Clurprevious electrophysiological study showed that neurosecretory neurons in the hypothalamic psraventticular nucleus receive serotonergic excitatory inputs from the midbrain raphe nuclei. We measured plasma vasopressin and oxytocin levels by radioimmunoassay and extracelhrlar serotonin level in the hypothalamic pamventricular nucleus by microdialysis with HPLC-ECD sfter stimulating the raphe nuclei. Stimulating electrodes were introduced stemotaxically into the dorsal, median, and pontine raphe nuclei of cats under a continuous intravenous infusion of pentobarbital(2mgikg/hr). Stimulation of the median raphe nucleus increased the plasma vasopmssin level significantly (prestimulus: 108.97 f 17.2 pg/ml. poststimulus: 153.2 + 20.0, mean + SE, pcO.001). Stimulation of the dorsal raphe nucleus did not affect the plasma vasopmssin level SignificsntIy.Pontine raphe stimulation decreased the plasma vssopmssin level. Stimulation of the raphe nuclei had no effects on oxytocin secretion. Serotonin level was increased by electrical stimulation of the raphe nuclei. Theses results suggest the vasopmssin secreting neurons receive excitatory synaptic inputs mainly from the median rsphe nucleus and the effective site of serotonin may be in the psrsventricular nucleus.
A HISTAMINE HZ RECEPTOR FEAR-RELATED JichiMedical
electric
School, Minamikawachi-machi, secretion
footshocks been
is suppressed
to
be
involved
20: 110-120,
antagonists
the
block
intracerebroventricularly level
response
the
significantly involved
suppression
SYNAPTIC
INPUTS
PARAVENTRICULAR
the
stress.
FROM NUCLEUS
THE
to
responses aimed
antagonists
other
response.
STOMACH
hand These
il
1
Histamine
to
stress
stress.
-of Physiology,
and tested
pyrilamine,
an Hl
results
show under
that
in the brain
histamine rats
receptor histamine
receptor
were
injected
footshocks
the suppressive
fear-related
TO TUBEROINFUNDIBULAR
OF THE HYPOTHALAMUS
whether
applied
& McCann,
with intermittent
abolished
by the pituitary
receptors (Libertun
Male
antagonist,
antagonist, in
emotional
NEURONS
for
vasopressin
the
did not brain
stress.
IN THE
IN RATS.
YUANZHE JINl. YOICHI UETA2,m2.2,
aYn’
Department
such as intermittently
at determining
emotional
an H2 receptor
secretion
stress
6: 143-148, 1988).
This study
On the
vasopressin
of vasopressin
emotional
prolactin
receptor
Ranitidine,
KINJI YAGI ---
329-04, Japan.
Res.,
in
response
with histamine
fear-related
influence
in
1976).
vasopressin
of vasopressin.
to
Tochigi
by fear-related
(Onaka & Yagi, Neurosci.
suggested
Neuroendocrinology,
plasma
TATSUSHI ONAKA -_---
EMOTIONAL STRESS
Vasopressin
have
ANTAGONIST BLOCKS THE SUPPRESSIVE VASOPRESSIN RESPONSE TO
lDeoartment of Phvsioloev, 2
icin
niversitv of
Occunstional and Environmental Health. Yshstanishiku. Kitakvushu 807. Jaosn, In male rats anesthetized with urethane (6OOmg/kg)and a-chlorslose (60mg/kg), extracellular recordings were made from tuberoinfundibular (Tl) neurons in the pamventricular nucleus (PVN) identifiid by antidromic stimulation of the median eminence. Electrical stimulation of the gastric branches of the vagus nerves excited 26 (72%) of 36 TI-neurons tested. Intravenous (0.51&at)
or intmperitoneaI(5pg/rat) administration of cholecystokinin (CCK-8) produced an excitation in 10 (63%) out of 16 TI-
neurons. The excitatory responses induced by CCK-8 were abolished after bilateral cervical vagotomy. Since a majority of TIneurons in tbe PVN syntlresixe corticotropin-releasing hormone (CRH) and project to the median eminence, the results suggest that putative CRI-Ineumns receive excitatory inputs from gastric afferents via vagus nerves.
is
EFFECTS
OF THE MIDBRAIN
HYPOTHALAMIC LEVELS
RAPHE
NUCLEUS
PARAVENTRICULAR
IN CATS.
STIMULATION
NUCLEUS
TOSHIMASA
ml,
ON SEROTONIN
AND ON PLASMA OSAKAl.
RELEASE
VASOPRESSIN
IN THE
AND OXYTOCIN
KEN’ICHI YAMAGUCm2,
TAKASHI
HIGUCH13, HIDE0 NEGOR03 AND HIROSHI YAh4ASHIT~1, lJ&ot. of avsiol.. Univ. of Occup and Environ. Health. Kitakvushu 8a2Deot. of Phvsiol.. Sch. of Med.. NiiPata Univ.. Niiaata 950. & 3Deot. of Phvsiol.. Fukui Med. Sch.. Fukui 910-11. Jam Clurprevious electrophysiological study showed that neurosecretory neurons in the hypothalamic psraventticular nucleus receive serotonergic excitatory inputs from the midbrain raphe nuclei. We measured plasma vasopressin and oxytocin levels by radioimmunoassay and extracelhrlar serotonin level in the hypothalamic pamventricular nucleus by microdialysis with HPLC-ECD sfter stimulating the raphe nuclei. Stimulating electrodes were introduced stemotaxically into the dorsal, median, and pontine raphe nuclei of cats under a continuous intravenous infusion of pentobarbital(2mgikg/hr). Stimulation of the median raphe nucleus increased the plasma vasopmssin level significantly (prestimulus: 108.97 f 17.2 pg/ml. poststimulus: 153.2 + 20.0, mean + SE, pcO.001). Stimulation of the dorsal raphe nucleus did not affect the plasma vasopmssin level SignificsntIy.Pontine raphe stimulation decreased the plasma vssopmssin level. Stimulation of the raphe nuclei had no effects on oxytocin secretion. Serotonin level was increased by electrical stimulation of the raphe nuclei. Theses results suggest the vasopmssin secreting neurons receive excitatory synaptic inputs mainly from the median rsphe nucleus and the effective site of serotonin may be in the psrsventricular nucleus.
A HISTAMINE HZ RECEPTOR FEAR-RELATED JichiMedical
electric
School, Minamikawachi-machi, secretion
footshocks been
is suppressed
to
be
involved
20: 110-120,
antagonists
the
block
intracerebroventricularly level
response
the
significantly involved
suppression
SYNAPTIC
INPUTS
PARAVENTRICULAR
the
stress.
FROM NUCLEUS
THE
to
responses aimed
antagonists
other
response.
STOMACH
hand These
il
1
Histamine
to
stress
stress.
-of Physiology,
and tested
pyrilamine,
an Hl
results
show under
that
in the brain
histamine rats
receptor histamine
receptor
were
injected
footshocks
the suppressive
fear-related
TO TUBEROINFUNDIBULAR
OF THE HYPOTHALAMUS
whether
applied
& McCann,
with intermittent
abolished
by the pituitary
receptors (Libertun
Male
antagonist,
antagonist, in
emotional
NEURONS
for
vasopressin
the
did not brain
stress.
IN THE
IN RATS.
YUANZHE JINl. YOICHI UETA2,m2.2,
aYn’
Department
such as intermittently
at determining
emotional
an H2 receptor
secretion
stress
6: 143-148, 1988).
This study
On the
vasopressin
of vasopressin
emotional
prolactin
receptor
Ranitidine,
KINJI YAGI ---
329-04, Japan.
Res.,
in
response
with histamine
fear-related
influence
in
1976).
vasopressin
of vasopressin.
to
Tochigi
by fear-related
(Onaka & Yagi, Neurosci.
suggested
Neuroendocrinology,
plasma
TATSUSHI ONAKA -_---
EMOTIONAL STRESS
Vasopressin
have
ANTAGONIST BLOCKS THE SUPPRESSIVE VASOPRESSIN RESPONSE TO
lDeoartment of Phvsioloev, 2
icin
niversitv of
Occunstional and Environmental Health. Yshstanishiku. Kitakvushu 807. Jaosn, In male rats anesthetized with urethane (6OOmg/kg)and a-chlorslose (60mg/kg), extracellular recordings were made from tuberoinfundibular (Tl) neurons in the pamventricular nucleus (PVN) identifiid by antidromic stimulation of the median eminence. Electrical stimulation of the gastric branches of the vagus nerves excited 26 (72%) of 36 TI-neurons tested. Intravenous (0.51&at)
or intmperitoneaI(5pg/rat) administration of cholecystokinin (CCK-8) produced an excitation in 10 (63%) out of 16 TI-
neurons. The excitatory responses induced by CCK-8 were abolished after bilateral cervical vagotomy. Since a majority of TIneurons in tbe PVN syntlresixe corticotropin-releasing hormone (CRH) and project to the median eminence, the results suggest that putative CRI-Ineumns receive excitatory inputs from gastric afferents via vagus nerves.
is