166
Aquaculture of Cyprinids
the O.P.
change with NaCl, KCl, CaC12, glycin or TRIS—HCI with the pH adjus—
ted
from 4 to
10.
These results
agree with those obtained by Morisawa et al.
(J. EXP. BIOL.,
1983, 102, 95—103). Sperm.activation,but not duration of
motility,is independent of the ionic composition of the dilution medium. The
longest period of motility is obtained in a medium containing 25 mM KCl and
50 mM NaCl
(buffered at pH 8.0 with 20 mM TRIS—HCI). In this medium about
90% of the sperm are still motile more than ten minutes after dilution. Using
stroboscopic observations and triton X 100 demembranation, followed by ATP
reactivation — procedures that have been developed to study sea urchin sperm
(GIBBONS et al., J. CELL. BIOL.,
1972,
75—97) — we showed that the
flagellar heating of live or demembranated—reactivated carp sperm has the
same
pattern of movement as the sperm of other species : their flagellum
shows
a
symmetrical, planag undulating curved wave. Isolation of carp flagel—
la is easy and, contrary to the results obtained with flagella from other
species, isolated carp flagella can be reactivated with a good percentage
of motility (50 to 60%). Some of these reactivated flagella exhibit a
pattern of motility similar to that observed for live and reactivated whole
sperm.
This result demonstrates that head—flagella interactions are not
necessary
to
obtain a beat pattern and forward motility identical to those
of
live sperm… Thus, flagella isolated from carp sperm provide a good model
for studying the relationship between wave propagation and pattern and
forward motility.
NEUROANAI‘OMÏCAL SUBSTRATE OF GONADOTROPIN SECRETÈON IN GOLDFISH
:
DOPAMINER—
GIC AND Gn—RH PREOPTICO—HYPOPHYSEAL PATHWAYS. O. KAH, J.G. DULKA, R.E. PETER,
and B. BRETON.
Labo&a£oic PhgM'o£och
Imiwœtom Caüu£…ü,
FRANCE.
The distribution of Gn—RH and that of catecholamines have been investigat6d
using antibodies for salmon Gn—RH and tyrosine—hydroxylase (TH). Cell bodies
immunopositive for Gn—RH have been found along a continous column extending
from the olfactory nerves and bulbs to the ventral telencephalon, the ventre—
lateral preoptic area and the ventre—lateral hypothalamus. A continuous fiber
tract
courses
along the perikarya described above and enters the pituitary,
so
that the precise origin of the Gn—RH fibers innervating the proximal pars
distalis is difficult to establish. Histofluorescence and immunohistochemical
detection
of TH indicate the presence of a catecholaminergic cell grouping
in
the rostro—ventral preoptic region. At least part of these cells have
been shown to containdopamine (DA) (KAH et al., Neurosci.Let., 48, 293—298),
which is known for inhibiting gonadotrophin secretion in goldfiËh (CHANG and
PETER, Neuroendocrinology,
351—357). In addition, dopaminergic fibers
have
been found in close contact with the gonadotrophs (KAH et al., Cell
Tissue Res.,
621—626), but also in the other regions of the pituitary.
In order to find the origin of the Gn—RH and DA fibers innervating the gonadotrophs, electrolytic lesions have been placed in a number of forebrain
areas
and their effects on the distribution of TH and Gn—RH fibers in the
pituitary were studied by immunocytocbemistry. Large lesions that destroyed
bilaterally
the rostro—lateral preoptic area resulted in a considerable
reduction of Gn—RH and TH staining in the proximal pars distalis. These
results
demonstrate the presence of preoptico—hypophyseal dopaminergic and
Gn—RH pathways in goldfish, confirming the essential role of the anterior
preoptic region in the regulation of gonadotrophin secretion.
Aquaculture of Cyprinids
the O.P.
change with NaCl, KCl, CaC12, glycin or TRIS—HCI with the pH adjus—
ted
from 4 to
10.
These results
agree with those obtained by Morisawa et al.
(J. EXP. BIOL.,
1983, 102, 95—103). Sperm.activation,but not duration of
motility,is independent of the ionic composition of the dilution medium. The
longest period of motility is obtained in a medium containing 25 mM KCl and
50 mM NaCl
(buffered at pH 8.0 with 20 mM TRIS—HCI). In this medium about
90% of the sperm are still motile more than ten minutes after dilution. Using
stroboscopic observations and triton X 100 demembranation, followed by ATP
reactivation — procedures that have been developed to study sea urchin sperm
(GIBBONS et al., J. CELL. BIOL.,
1972,
75—97) — we showed that the
flagellar heating of live or demembranated—reactivated carp sperm has the
same
pattern of movement as the sperm of other species : their flagellum
shows
a
symmetrical, planag undulating curved wave. Isolation of carp flagel—
la is easy and, contrary to the results obtained with flagella from other
species, isolated carp flagella can be reactivated with a good percentage
of motility (50 to 60%). Some of these reactivated flagella exhibit a
pattern of motility similar to that observed for live and reactivated whole
sperm.
This result demonstrates that head—flagella interactions are not
necessary
to
obtain a beat pattern and forward motility identical to those
of
live sperm… Thus, flagella isolated from carp sperm provide a good model
for studying the relationship between wave propagation and pattern and
forward motility.
NEUROANAI‘OMÏCAL SUBSTRATE OF GONADOTROPIN SECRETÈON IN GOLDFISH
:
DOPAMINER—
GIC AND Gn—RH PREOPTICO—HYPOPHYSEAL PATHWAYS. O. KAH, J.G. DULKA, R.E. PETER,
and B. BRETON.
Labo&a£oic PhgM'o£och
Imiwœtom Caüu£…ü,
FRANCE.
The distribution of Gn—RH and that of catecholamines have been investigat6d
using antibodies for salmon Gn—RH and tyrosine—hydroxylase (TH). Cell bodies
immunopositive for Gn—RH have been found along a continous column extending
from the olfactory nerves and bulbs to the ventral telencephalon, the ventre—
lateral preoptic area and the ventre—lateral hypothalamus. A continuous fiber
tract
courses
along the perikarya described above and enters the pituitary,
so
that the precise origin of the Gn—RH fibers innervating the proximal pars
distalis is difficult to establish. Histofluorescence and immunohistochemical
detection
of TH indicate the presence of a catecholaminergic cell grouping
in
the rostro—ventral preoptic region. At least part of these cells have
been shown to containdopamine (DA) (KAH et al., Neurosci.Let., 48, 293—298),
which is known for inhibiting gonadotrophin secretion in goldfiËh (CHANG and
PETER, Neuroendocrinology,
351—357). In addition, dopaminergic fibers
have
been found in close contact with the gonadotrophs (KAH et al., Cell
Tissue Res.,
621—626), but also in the other regions of the pituitary.
In order to find the origin of the Gn—RH and DA fibers innervating the gonadotrophs, electrolytic lesions have been placed in a number of forebrain
areas
and their effects on the distribution of TH and Gn—RH fibers in the
pituitary were studied by immunocytocbemistry. Large lesions that destroyed
bilaterally
the rostro—lateral preoptic area resulted in a considerable
reduction of Gn—RH and TH staining in the proximal pars distalis. These
results
demonstrate the presence of preoptico—hypophyseal dopaminergic and
Gn—RH pathways in goldfish, confirming the essential role of the anterior
preoptic region in the regulation of gonadotrophin secretion.