SEARCH · PubMed Health

Results for “Microinjection”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 649 records · Page 36Linked to original sources

PubMed1996

[Effect of intrahippocampal microinjection of enkephalin on cellular immune function and brain IL-1 alpha gene expression in rat].

The effect of intrahippocampal microinjection of enkephalin on cellular immune function and hippocampal IL-1 alpha gene expression was studied in rats. The results showed that: (1) The proliferation activity of splenic lymphocytes stimulated by Con A was significantly increased with microinjection of Leu-enkephalin 1 microliter (18 mmol/L) or Met-enkephalin 1 microliter (18 mmol/L) into bilateral hippocampus, but was inhibited by Lipopolysaccharide 1 microliter (50 ng/microliter). The proliferative response of splenic lymphocytes to Leu-enkephalin still persisted after bilateral adrenalectomy. Low doses of Leu- or Met-enkephalin (10(-10), 10(-11) mol/L) were also capable of causing proliferative activity of the Con A- stimulated cultured splenic lymphocytes in vitro. (2) Using RT-PCR technique, IL-1 alpha gene expression was detected in hippocampus 90 min after bilateral intrahippocampal injection of LPS. The LPS-induced IL-1 alpha gene expression in hippocampus could no longer be detected 30 min after microinjection of Met- or Leu-enkephalin into hippocampus. The above results suggested that intrahippocampal enkephalin might play an important role in neuro-immunomodulation by enhancing the inhibition of IL-1 alpha gene expression in hippocampal formation.

Adrenalectomy↗

PubMed1998

Microinjected antisera against ductin affect gastrulation in Drosophila melanogaster.

Ductin is a putative connexon-forming protein in gap junctions of arthropods. To analyze the role of gap-junction mediated cell-cell communication during Drosophila embryogenesis, we used two different polyclonal anti-ductin sera. One antiserum was directed against ductin isolated from gap junctions of the lobster Nephrops whilst the other was raised against a nonapeptide at the N-terminus of ductin from Drosophila. Both antisera were found to inhibit, when microinjected into Drosophila ovarian follicles, the intercellular exchange of fluorescent tracer molecules between oocyte and follicle epithelium. This result indicates that Drosophila ductin plays a decisive role in gap-junctional communication and confirms the cytoplasmic location of the ductin N-terminus in gap junctions. On immunofluorescence preparations and immunoblots, the anti-ductin sera specifically recognized ovarian as well as embryonic antigens. Following microinjections of the antisera into embryos prior to gastrulation, significantly reduced rates of hatching larvae were obtained. Moreover, microinjections into the mid-ventral region of the embryos resulted in specific ventral defects that depended on the concentration of the ductin antibodies. In particular, larvae with ventral holes in their cuticles occurred with high frequency. During gastrulation, antiserum-injected embryos often developed defects in the middle region of their ventral furrow. Here, mesodermal cells failed to invaginate correctly and, thus, no cuticle was formed. We conclude that, during Drosophila embryogenesis, gap-junctional communication is required for epithelial integrity and morphogenetic events.

Animals↗

PubMed1997

[Effect of microinjection of CRH into rat central nucleus of amygdala on blood pressure and its central mechanism].

The effect of microinjection of corticotropin releasing hormone (CRH) into the central nucleus of amygdala (CeA) on blood pressure was examined in Wistar rats anaesthetized with pentobarbital sodium. The results were as follows: (1) Microinjection of CRH 100, 500 ng into the CeA produced a dose-dependent increase in blood pressure. The response occurred 5 min after injection and lasted for at least 1 h. (2) The response could be blocked by injection of CRH receptor antagonist alpha-helical CRH9-41 into CeA. (3) Lateral ventricle injection of naloxone could also attenuate the pressor response of CRH. (4) After injection of alpha-helical CRH9-41 into nucleus of solitary tract, the pressor response of CRH was diminished. The results suggest that the pressor effect induced by microinjection of CRH into the CeA might be partly mediated through opioid system via a descending pathway from CeA to NTS.

Amygdala↗

PubMed1997

[Effect of microinjection of adrenaline (E) into the rostral ventrolateral medulla on the parameters of the hemorrheology].

Experiments were performed on SD rats. It was found that hyperviscosity could be induced by restrained conscious rats. Microinjection of adrenaline (E) into the rostral ventrolateral medulla (rVLM) resulted in a facilitatory increase in blood viscosity, which was blocked by bilateral microinjection of alpha-adrenoceptor antagonist (phentola mine) into the same area, but not by beta-adrenocetor antagonist (propranolol). Pretreatment of rVLM area with 6-hydroxydopamine (6-OHDA) or microinjection of phentolamine abolished stress-induced hyperviscosity, while propranolol was without effect. Apparently the E caused increase of the blood viscosity or stress-induced hyperviscosity may be mediated by activation of alpha-adrenoceptor in the rVLM.

Animals↗

PubMed1997

[Effects of microinjection of sodium glutamate and glycine into ventrolateral nucleus of tractus solitarius on the discharges of phrenic nerve in rabbits].

The effects of microinjection of sodium glutamate and glycine into ventrolateral nucleus of tractus solitarius (VLNTS) on the discharges of phrenic nerve were observed on 40 anaesthetized, vagotomized, paralyzed and artificially ventilated rabbits. The results were as follows: Phrenic nerve discharges were increased, inspiratory duration prolonged, expiratory duration shortened and respiratory frequency not changed by microinjection of sodium glutamate into VLNTS. While by microinjection of glycine, phrenic nerve discharges were decreased, even abolished, inspiratory duration shortened, expiratory duration irregularly prolonged and respiratory frequency decreased. The above results show that VLNTS exert important effects on the genesis of respiratory rhythm.

Animals↗

PubMed1996

Detection of microinjected genes in bovine preimplantation embryos with combined DNA digestion and polymerase chain reaction.

We have developed a simple digestion-polymerase chain reaction (PCR) assay for a simultaneous transgene detection and sexing of pronucleus-injected bovine preimplantation embryos. Bovine embryos were microinjected with dam-methylated gene construct and cultured in vitro for 6-7 days after the injections. The developed blastocysts and compact morulae were bisected and the embryonic biopsies representing mainly trophoblasts were subjected to the digestion-PCR, while the biopsied embryos remained in culture. Embryonic DNA was released with proteinase K and the samples were digested with a Dpnl-Bal31 mixture before the PCR amplification of the transgene, bovine alpha S1-casein, and bovine Y-chromosome fragments in the same reaction. The whole assay from biopsy to electrophoresis took less than 6 hr. The digestion removed up to 50 fg of dam-methylated transgene copies (unintegrated or contaminants) and also a few hundred copies of contaminating PCR products from the embryonic samples. The digestion-PCR assay eliminated all transgene contaminations from noninjected blastocysts, which were exposed to the microinjection DNA during the stay in injection chambers, and reduced the amount of transgene-positive embryos among pronucleus-injected blastocysts as compared with unmodified PCR. Analysis of 486 microinjected bovine embryo biopsies in 13 separate experiments revealed that we were able to sex 398 (82%) of the biopsies and 77 (19%) of the biopsies were scored as transgene positive and 57 (14%) as transgene questionable. Upon reanalysis of 41 of the biopsied embryos, 38 (93%) of the embryos were observed to be transgene negative and 2 questionable in both assays and uneven distribution of transgene copies was observed in one embryo. The results from sexing were in accordance with biopsies and remaining embryos in 38 (93%) of the embryos.

Animals↗

PubMed1990

Morphogenesis of endoplasmic reticulum in Xenopus oocytes after microinjection of rat liver smooth microsomes.

We have determined the kinetics of endoplasmic reticulum (ER) reconstitution following insertion of rat-liver smooth microsomes (SM) into Xenopus oocyte cytoplasm using electron microscopy as well as cytochemistry and thick-section 3-dimensional reconstruction. Oocytes were fixed 0, 10, 20, 40, 80, and 120 min after microinjection with SM and processed for thin- and thick-section electron microscopy. At 0 min postinjection, rat liver SM were observed as small vesicles and were loosely dispersed amongst oocyte organelles. At 10 min, tubules were discerned among many elongate vesicles; and these structures comprised large cytoplasmic regions delimited by mitochondria and yolk platelets. By 20 min, segregation of transplanted organelles yielded yolk-platelet-free regions composed of few vesicles but increasingly numerous, long and anastomosing tubules. By 40 min, a network with numerous tubular branches and fenestrations was observed among the few remaining vesicles. By 80 min, transformation of rat liver SM into a complex network of branching and anastomosing tubules was complete. Three-dimensional reconstruction revealed the network to be composed of interconnecting elements consisting of anastomosing tubules. The reconstituted network of anastomosing tubules in Xenopus oocytes was compared to the network of anastomosing tubules in rat liver hepatocytes and was found to be essentially identical. Network formation occurred in oocytes pretreated with either vinblastine (40 microM) or nocodazole (0.166 microM), and network organization was maintained in oocytes treated with the same drugs after microinjection and reconstitution. We conclude that SM retain sufficient molecular information for rapid self-assembly into structures resembling those in the cells from which they were derived. Both the assembly and maintenance of ER structure in oocyte cytoplasm are microtubule-independent. The formation of such structures following microinjection of SM into living cells provides a unique assay for this type of membrane subfraction.

Animals↗

PubMed1996

Isolated maize zygotes mimic in vivo embryonic development and express microinjected genes when cultured in vitro.

We established conditions for the regeneration of natural maize zygotes isolated from pollinated plants with the goal of investigating the molecular control of early embryogenesis in higher plants. Viable zygotes were excised from embryo sacs by minimal enzymatic digestion and microdissection. Viable zygotes transferred to coculture with androgenic microspores from barley developed into embryo-like structures in 61% of the cases. No development was observed when zygotes were cultured in the presence of maize anthers undergoing androgenetic embryogenesis. Zygote-derived embryo-like structures regenerated into fertile plants through secondary embryogenesis when transferred to solid medium. The first zygotic division was asymmetrical and bipolar structures similar to pretransitional embryos observed in planta were later produced as observed using light and electron microscopy. Conditions for efficient microinjection of DNA into zygotes were established. Calcofluor and PATAG staining of zygotes showed that cell wall regeneration occurred as early as 20 min after enzymatic isolation and that after 2 hr, each zygote was bordered with cell wall material. Through quantitative microphotometry, DNA synthesis during the first cell cycle of the zygote was shown to occur between isolation and 12 hr of culture. Microinjection of two types of reporter genes (GUS gene and anthocyanin regulatory genes) demonstrates transient expression in plant zygotes. On average, 3.5% of microinjected zygotes showed transgenic expression. Reporter gene expression was observed in zygotes at different time points of their first cell cycle.

Cell Cycle↗

PubMed1996

Intracellular Microinjection: A Powerful Tool in the Study of Neuronal Gene Expression and Function

Neurons in primary culture provide a useful experimental system with which to explore the functions of neuronal genes and the mechanisms regulating their expression. Both types of study call for transfection of neurons with plasmid DNA constructs that express either the gene of interest or a reporter gene under the transcriptional control of sequences from the gene being studied. However, the phenotypic heterogeneity and limited cell numbers that are often a feature of primary neuronal culture preparations mean that methods commonly used for bulk transfection and analysis of cell line cultures are inappropriate or difficult to apply. Intracellular microinjection provides the experimenter with the means to direct transfection into a specific cell type with high efficiency and is ideally suited for work with small cell numbers. Moreover, developments in microinjection technology and in methods of analyzing gene expression in small numbers of cells mean that many of the apparent limitations of the technique are now being overcome. The microinjection procedures that have been used in our laboratory to study neuropeptide gene expression in cultured mature mammalian sensory neurons are described.

Journal Article↗

PubMed1977

The effect of intraspinal microinjections of 6-hydroxydopamine on the inhibitory influence exerted on spinal sympathetic activity by the baroreceptors.

1. The inhibition of spinal somato-sympathetic reflex activity, following electrical stimulation of the carotid sinus nerve in cats has been studied before and after chronic intraspinal microinjections of 6-hydroxydopamine into the cervical spinal cord. 2. The effect of these microinjections on bulbospinal catecholaminergic neurones was assessed using the formaldehyde fluorescence technique for the demonstration of intraneuronal monoamines. 3. In 5 6-hydroxydopamine-treated animals, inhibition of the spinal sympathetic reflex response following stimulation of the sinus nerve was reduced compared to control untreated animals. When damage to the bulbo-spinal catecholamine system in the dorso-lateral funiculi was extensive, the inhibition was almost completely abolished; with more limited destruction a lesser effect was observed. 4. These effects were not seen in a group of control animals, which received intraspinal microinjections of the 5-hydroxytryptamine neurotoxin 5,6-dihydroxytryptamine and which showed damage to the indoleaminergic neuronal system but no damage to the bulbo-spinal catecholaminergic system. 5. It is concluded that the inhibitory effects of the baroreceptors on spinal sympathetic activity are mediated by bulbo-spinal catecholaminergic neurones.

Animals↗

PubMed1988

Response suppression in rats after bilateral microinjection of 5-hydroxytryptophan in lateral hypothalamus.

Studies using the 5-hydroxytryptophan (5-HTP) animal model of depression have led to the development of the hypersensitive postsynaptic serotonin receptor theory of depression. To demonstrate more clearly that the 5-HTP-induced suppression is a centrally mediated phenomenon, rats were implanted with bilateral cannulae in the lateral hypothalamus and received microinjections of D,L-5-HTP (100-500 ng) 15 min after the start of a VI operant session (milk reinforcement). Significant decreases in responding were observed that were comparable to those obtained after a systemic injection of 50 mg/kg D,L-5-HTP. Rats receiving a microinjection of 5-HTP in the posterior hypothalamus did not exhibit a behavioral effect. Rats working on shock-avoidance schedules did not demonstrate response suppression following microinjection of 5-HTP into the lateral hypothalamus, which is the same result as that following systemic 5-HTP administration. These data support the important role previously assigned to central 5-HT mechanisms in the 5-HTP animal model of depression.

5-Hydroxytryptophan↗

PubMed1979

Amphetamine-induced circling behavior in rats: effects of unilateral microinjections of GABA and GABA-related drugs into substantia nigra.

In these experiments, the GABA control upon dopaminergic nigrostriatal neurons has been investigated using circling behavior in the rat. Chronically cannulated rats were given D-amphetamine (2 mg/kg i.p.) 45 min before unilateral microinjection (0.2 microliter/2 min) into the substantia nigra (SN) of GABA, muscimol, chlordiazepoxide (CDP) or bicuculline. Circling behavior was continuously recorded for 165 min using an automated rotometer. (1) Non-microinjected control rats exhibit a 'spontaneous' circling behavior after amphetamine. (2) When applied to the SN contralateral to the preferential side of the 'spontaneous' rotations, saline enhances contraversive circling; GABA (5 X 10(-5)M), CDP (5 X 10(-5)M) and muscimol (5 x 10(-7)M, 5 X 10(-8)M) counteract this effect and induce (except CDP) light ipsiversive rotations; GABA (10(-2)M) and muscimol (5 x 10(-5)M) further enhance contraversive turning. (3) When applied to the SN ipsilateral to the preferential side of the 'spontaneous' rotations, saline has no marked effect on the ipsiversive circling behavior but induces weak contraversive turning; GABA (5 X 10(-5)M), CDP (5 X 10(-5)M) and muscimol (5 x 10(-8)M) enhance the ipsiversive rotations; GABA (10(-2)M) and muscimol (5 x 10(-5)M) transiently decrease the ipsiversive circling; bicuculline (5 x 10(-5)M) induces a vigorous contraversive turning associated with a transient inhibition of the ipsiversive rotations. These results suggest that the activity of the nigral neurons is presumably stimulated by the microinjection itself, by bicuculline and, to a lesser extent, by high concentrations of GABA and muscimol, and inhibited by low concentrations of GABA, muscimol and CDP. These findings could further support the hypotheses of a GABAergic inhibitory control upon DA nigrostriatal pathways and of a GABA-like activity of CDP.

Animals↗

PubMed1983

Microinjection of morphine into nucleus reticularis paragigantocellularis of the rat suppresses spontaneous activity of nucleus raphe magnus neurons.

Microinjection of morphine into nucleus reticularis paragigantocellularis of anesthetized rats had differential effects on spontaneous firing of neurons in nucleus raphe magnus (NRM) depending upon the dose of morphine administered. Microinjection of 1 microgram of morphine, a dose which has reliable antinociceptive effects in awake animals, had predominantly suppressive effects on NRM spontaneous firing. Microinjection of 0.35 micrograms of morphine, a dose which has small and unreliable antinociceptive effects in awake animals, had little effect on the activity of NRM cells.

Animals↗

PubMed1986

Opiate microinjections into midbrain do not affect the aversiveness of caudal trigeminal stimulation but produce somatotopically organized peripheral hypoalgesia.

High-dose microinjections of morphine sulfate (15 micrograms) and (D-Ala2)-Met-enkephalin (30 micrograms) were made into the ventral periaqueductal gray of rats. Consistent with previous reports using lower doses, both opiates produced hypoalgesia for noxious thermal stimuli applied to the upper and lower body. More hypoalgesia was observed on the face than on the hind legs or tail. Current thresholds of aversive reaction to stimulation in the trigeminal subnucleus caudalis were unaffected by microinjection of either opiate. Systemic injections of 6 mg/kg morphine sulfate profoundly inhibited defense responses to peripheral noxious stimuli and significantly elevated aversive reaction thresholds for stimulation in the trigeminal subnucleus caudalis. Aversive reactions to stimulation in the dorsal periaqueductal gray remained unaffected by either microinjected or systemically administered opiates.

Animals↗

PubMed1987

GABAergic modulation of the analgesic effects of morphine microinjected in the ventral periaqueductal gray matter of the rat.

The possibility that GABAergic neurons in the ventral periaqueductal gray matter modulate the analgesic effects of morphine microinjected into this brain area was investigated in the rat. Microinjection of 4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin 3-ol (THIP) (0.4 microgram in 0.2 microliter), a GABA agonist, in the ventral periaqueductal gray matter significantly reversed the increase of tail-flick latency induced by a prior injection of morphine sulfate (4 micrograms in 0.2 microliter) at the same site. Conversely, microinjection in the same region of picrotoxin (10 ng in 0.2 microliter), a GABA antagonist, significantly potentiated the analgesic effect of the same dose of morphine. These results suggest the existence of GABAergic neurons that tonically inhibit periaqueductal gray output neurons involved in centrifugal pain inhibition. The analgesic effects of opiates may, at least in part, result from disinhibition of these GABAergic neurons.

Animals↗

PubMed1989

Substance P and GABAergic effects on adrenal and autonomic function evoked by microinjections into trigeminal subnucleus caudalis in the cat.

To assess the contribution of putative neurotransmitters in mediating changes in adrenal and autonomic function evoked by activation of medullary dorsal horn neurons, microinjections of substance P, bicuculline methiodide, or muscimol were directed at various laminac of trigeminal subnucleus caudalis in the anesthetized cat. Injections of substance P (35.6 pmol) into the superficial layers (lamina I-II) of subnucleus caudalis increased the adrenal secretion of epinephrine (+8.3 +/- 2.3 ng/min, P less than 0.01), arterial pressure (+11 +/- 5.3 mm Hg, P less than 0.01), and heart rate (+19.4 +/- 4.9 beats/min, P less than 0.01) by 1 min, and increased the plasma concentration of adrenocorticotropin (+26 +/- 10 pg/ml, P less than 0.01) by 3 min. Substance P injections into the magnocellular layers (lamina III-IV) or deep magnocellular layers (lamina V-VI) had no significant effects. Microinjections of the GABAA antagonist, bicuculline methiodide (62.4 pmol), into the superficial layers of subnucleus caudalis increased the adrenal secretion of epinephrine (+4.5 +/- 3.2 ng/min, P less than 0.01) by 1 min, whereas injections of the GABAA agonist, muscimol (280 pmol), decreased the secretion (-5.8 +/- 2.8 ng/min, P less than 0.05) by 6 min. Arterial pressure increased after bicuculline (+17.8 +/- 8.2 mm Hg, P less than 0.01) and decreased after muscimol (-6.3 +/- 2.9 mm Hg, P less than 0.01) injections into the superficial layers. Injections of bicuculline or muscimol into the magnocellular layers or into the deep magnocellular layers had no effect on adrenal secretion of catecholamines or on systemic cardiovascular function. Peripheral venous concentrations of adrenocorticotropin were not affected significantly by microinjections of GABAergic agents regardless of the laminar site of injection within subnucleus caudalis. Equivalent volume injections of artificial cerebrospinal fluid into the superficial laminae of subnucleus caudalis had no significant influence on any measured variable. Substance P-evoked changes in the adrenal secretion of epinephrine were not correlated with changes in adrenal venous blood flow, whereas bicuculline- and muscimol-evoked changes in adrenal secretion of catecholamines were positively correlated with changes in adrenal blood flow (P less than 0.01). The results indicate that substance P and GABA contribute significantly to the trigeminal control of adrenal and autonomic function by acting on neurons in the superficial layers of subnucleus caudalis, a brainstem region that processes nociceptive sensory information.

Adrenal Glands↗

PubMed1987

Intracellular fate of ferritin in HeLa cells following microinjection.

It is known that following iron overload newly synthesized ferritin molecules accumulate in lysosomes. However, the way in which these molecules enter the lysosomes has not been clarified. In order to assess if these molecules can be taken up by lysosomes from the cell sap, i.e., by way of autophagy, ferritin was introduced into HeLa cells through microinjection with a glass capillary. The fate of the ferritin was studied after varying intervals with the electron microscope. Shortly after microinjection ferritin molecules could be observed in the cell sap. After both 1 and 2 h, they were found in clusters and still mainly in the cell sap. After 4 h, ferritin molecules were present not only in the cell sap and in autophagic vacuoles but also in occasional secondary lysosomes. After 12 h, they were seen mainly in lysosomes, undergoing degradation. In no instance were ferritin molecules translocated into other organelles such as mitochondria, Golgi apparatus, or endoplasmic reticulum. The present study demonstrates that ferritin can be introduced into cells by glass capillary microinjection without cell damage. From its initial location in the cell sap ferritin is taken up into the lysosomal vacuome. Autophagy is considered to be the principal mechanism for the transfer of the ferritin molecules into lysosomes.

Autophagy↗

PubMed1982

Suppression of apomorphine-induced oral stereotypy in rats by microinjection of muscimol into midbrain.

Rats with large lesions of the superior colliculus do not display the oral stereotypy normally induced by high systemic doses of dopamine-agonists. It has been suggested that collicular lesions have such an effect because they destroy the GABAergic nigrotectal pathway. This suggestion was investigated by observing the effects of bilateral microinjections of the GABA-agonist muscimol into midbrain sites in rats given 8 mg/kg subcutaneous apomorphine. A low dose of muscimol (25 ng in 0.5 ul saline/side) injected into regions of the superior colliculus with nigrotectal innervation almost abolished apomorphine-induced licking and gnawing. Control microinjections of saline into the superior colliculus, or of muscimol into overlying cerebral cortex, were ineffective. This result is consistent with the GABAergic nigrotectal projection being important for the expression of dopamine-related oral stereotypy. It was also found, however, that 25 ng of muscimol suppressed oral stereotypy when microinjected into the mesencephalic reticular formation underlying the superior colliculus. The anatomical basis of this latter effect is uncertain.

Animals↗