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J C Holstege

Publications and source records attributed to J C Holstege.

33 records · Page 2Linked to original sources
PubMed1991

Ultrastructural aspects of the coeruleo-spinal projection.

Few studies have focussed on the ultrastructure of the coeruleo-spinal projection. In rat the projections from the area of the locus coeruleus (LC) and subcoeruleus (SC) to lumbar motoneuronal cell groups exhibited two different types of terminals: E-type terminals, containing many very small vesicles and S-type terminals, containing many spherical vesicles and an occasional dense-cored vesicle. These findings are in agreement with data indicating the existence of a noradrenergic (NA) and a non-NA projection from the area of the LC and SC to the spinal cord. A study on dopamine-beta-hydroxylase (D beta H)-immunoreactive terminals in lumbar motoneuronal cell groups showed that they contained several granular vesicles, which were not found in the E- and S-type terminals. Only a few immunoreactive terminals exhibited a synaptic specialization in a single, thin section. A low incidence of synaptic junctions was also found for the E-type terminals, but not for the S-type. Based on this and other data, it is suggested that the E-type terminal is NA, while the S-type may contain a non-NA transmitter, possibly acetylcholine. A low incidence of synaptic junctions in single, thin sections may indicate the presence of non-synaptic NA terminals, but direct evidence from serial-section analysis is not available. In the superficial dorsal horn, terminals derived from the area of the LC and SC were identified at the ultrastructural level in two studies, one using the anterograde degeneration technique in opossum, the other (presented in this chapter) using WGA-HRP anterograde tracing in rat. It was found in both studies that most of the labeled structures were small axons (mostly unmyelinated), while few terminals were labeled. They contained mostly spherical vesicles and, according to the degeneration study, a variable number of dense-cored vesicles. The labeled terminals appeared to make regular synaptic contacts mostly with small dendrites and occasionally with spines. They were not present in glomeruli or engaged in presynaptic arrangements. A study on NA terminals showed similar results, although large granular vesicles were not observed and fewer synapses were seen. On the few data available at present it is concluded that in the spinal superficial dorsal horn, most terminals derived from the area of the LC and SC are NA and establish conventional synapses. However, a non-NA component cannot be excluded.

Animals↗
PubMed1991

Vasopressin immunoreactive fibers and neurons in the dorsal pontine tegmentum of the rat, monkey and human.

It is now well established that extensive extrahypothalamic vasopressin (VP) systems exist in the rat, monkey and human brain. There are marked differences between species, but in each case VP nuclei provide dense afferents to the dorsal pontine tegmentum. Here VP may play a role in the mechanisms exerted by the locus coeruleus (LC) neurons, possibly both as a neurotransmitter and as a neuromodulator. Although we are aware of some properties of VP systems, e.g., gonadal steroid dependency in the rat, major gaps characterize our knowledge of its anatomy. With regard to the interaction of VP with the LC in the brainstem of mammals some of the questions which stand out are: (1) Is VP really being biosynthesized and transported by LC cells and, if not, what is its function within these cells? (2) Is there a structural difference between male and female LC neurons in the rat as a consequence of the sex-dimorphic VP innervation? (3) What is the origin of VP afferents in the dorsal pontine tegmentum of the (non)human primate and are these afferents also controlled by gonadal steroids? Research strategies to answer these questions will provide us with information to resolve some of the current inconsistencies about the anatomy and the function of the VP and LC systems in the brain.

Afferent Pathways↗
PubMed1991

Ultrastructural evidence for GABAergic brain stem projections to spinal motoneurons in the rat.

In the present ultrastructural study in the rat, it was determined whether GABA was present in projections descending from the ventromedial reticular formation of the lower brain stem to motoneuronal cell groups in the lumbar spinal cord. For this purpose, the anterograde transport of WGA-HRP was combined with the postembedding immunogold technique for GABA, with the advantage that both markers could be visualized simultaneously in a single terminal. In 4 rats, WGA-HRP was injected in the ventromedial part of the brain stem reticular formation at levels between the rostral inferior olive and the caudal part of the facial nucleus. Vibratome sections were cut from the lumbar spinal cord, reacted for WGA-HRP, and processed for electron microscopy. Ultrathin sections containing the lateral motoneuronal cell groups were cut and treated following the immunogold technique using a polyclonal antibody directed against GABA. It was found that nearly 40% of the terminal profiles that were labeled with WGA-HRP reaction products from the ventromedial brain stem were also labeled for GABA (double labeled). Most of the double-labeled terminals (81%) were F-type (containing many flattened vesicles), 12% were G-type (containing many granular vesicles), and 7% were S-type (containing many spherical vesicles). The majority of the double-labeled terminals contacted proximal dendrites. It is argued that the descending GABAergic projection produces a general inhibitory effect on spinal motoneurons, counteracting the general facilitation produced by the serotonergic projection derived from the same brain stem area.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Intracellular labeling of neurons in the medial accessory olive of the cat: II. Ultrastructure of dendritic spines and their GABAergic innervation.

In order to describe the morphology of dendritic spines of identified neurons in the cat inferior olive together with their gamma-aminobutyric acid (GABA) synaptic input, a technique was used combining intracellular labeling of horseradish peroxidase with postembedding gold-immunocytochemistry. With this technique physiologically identified olivary cells were reconstructed with the light microscope, and the horseradish peroxidase reaction product and immunogold labeling were subsequently examined in serial sections at the ultrastructural level. In addition, a degenerating neuron was observed, resulting in a triple labeling in single ultrathin sections. Quantitative and three-dimensional analysis showed that the dendritic spines were composed of long, thin stalks ending in one or more spine heads. The spines of cells located in the caudal half of the medial accessory olive (type I cells, characterized by dendrites which run away from the soma) were found to be less complex than those of cells located rostrally in this olivary subnucleus (type II cells, characterized by dendrites which tend to turn back towards the soma). Most, if not all, of the spines of both cell types were located within glomeruli. On average, the spines within individual glomeruli originated from 6 different dendrites (with a maximum of 8). Different spines within the same glomerulus were never derived from different dendrites of the same olivary neuron, but single spines frequently gave rise to several spine heads, which could be located either within different glomeruli or inside a single glomerulus. The glomerular spine heads originating from the same spine were rarely located near one another. All spines and most of the spine heads were contacted by both GABAergic and non-GABAergic terminals. Most of the GABAergic terminals contained pleomorphical vesicles and displayed symmetric synapses whereas the non-GABAergic terminals showed usually round to oval vesicles and asymmetric synapses.

Animals↗
PubMed1990

Intracellular labeling of neurons in the medial accessory olive of the cat: III. Ultrastructure of axon hillock and initial segment and their GABAergic innervation.

The gamma-aminobutyric acid (GABA) synaptic input of identified axons in the cat inferior olive was studied by use of combination of intracellular labeling with horseradish peroxidase and postembedding gold-immunocytochemistry. With this technique olivary cells were physiologically identified and light microscopically reconstructed, and the horseradish peroxidase reaction product and the immunogold labeling were subsequently simultaneously visualized for electron microscopic investigation with the use of serial ultrathin sections. The axons of cell type I (characterized by dendrites which radiate away from the cell body) originated from the soma, whereas those of type II neurons (characterized by dendritic trees which curve back towards the soma) were derived from a primary dendrite. The axons of olivary neurons stand out by the length of their axon hillock (up to 21 microns) and initial segment (up to 40 microns). The hillock forms various spiny appendages which were located within glomeruli together with dendritic spines of other olivary neurons. Axonal spines of type II neurons were more numerous and complex looking than those of type I. The axonal spines, the shaft of the axon hillock, and the transition between the hillock and initial segment were primarily innervated by GABAergic terminals (65%) but non-GABAergic terminals (35%) were present as well. The terminals apposed to the axons of type I neurons contacted mainly the axonal shafts, whereas most of the terminals adjacent to the axons of type II neurons established synaptic contacts with the axonal spines. The initial segments were largely devoid of synaptic input. Distally, the initial segment acquired a myelin sheath.

Animals↗
PubMed1990

The distribution of GABA in lumbar motoneuronal cell groups. A quantitative ultrastructural study in rat.

gamma-Aminobutyric acid (GABA)-containing profiles were identified at the ultrastructural level in rat lumbar motoneuronal cell groups by means of the postembedding immunogold technique, which is assumed to give very accurate quantitative results. It was found that 84.5% of the GABA-labeled terminals were of the F-type (containing many flattened vesicles), whereas P-type terminals (presynaptic to other terminals) constituted 9.2% of the GABAergic terminal profiles. A few of the GABA-labeled terminal profiles (1.7%) were G-type (containing many granular vesicles and presumed serotonergic), possibly indicating co-existence of GABA and serotonin. It is concluded that in spinal motoneuronal cell groups the large majority of the GABAergic terminal profiles were involved in postsynaptic inhibition of motoneurons, while only a minority was engaged in presynaptic inhibition.

Animals↗
PubMed1990

Mesodiencephalic and cerebellar terminals terminate upon the same dendritic spines in the glomeruli of the cat and rat inferior olive: an ultrastructural study using a combination of [3H]leucine and wheat germ agglutinin coupled horseradish peroxidase anterograde tracing.

The mesodiencephalic and cerebellar afferents in the rostral medial accessory and principal olive of the cat and rat were studied following anterograde transport of tritiated leucine combined with anterograde transport of wheat germ agglutinin coupled horseradish peroxidase in the same animals. In all studied areas at least one-third of the labelled glomeruli appeared to contain both mesodiencephalic and cerebellar terminals. In many of these cases it was found that the terminals from both afferent systems contacted the same dendritic spines. Therefore, these olivary spines may be, as will be discussed, well suited for being involved in a timing process.

Animals↗
PubMed1989

Ultrastructural study of the GABAergic, cerebellar, and mesodiencephalic innervation of the cat medial accessory olive: anterograde tracing combined with immunocytochemistry.

The rostral medial accessory olive (MAO) of the cat was studied by using an ultrastructural technique combining wheat germ agglutinin-coupled horseradish peroxidase (WGA-HRP) anterograde tracing and postembedding GABA immunocytochemistry. One group of cats received a WGA-HRP injection in the posterior interposed nucleus of the cerebellum and another group received an injection in the nucleus of Darkschewitsch. Based on differences in their morphology three types of GABAergic and three types of nonGABAergic terminals were observed. One type of GABAergic terminal was often GABA/WGA-HRP double-labeled in the cerebellar experiments, and one type of nonGABAergic terminal was often WGA-HRP-labeled in the mesodiencephalic experiments. Following injections of WGA-HRP in the cerebellar nuclei virtually all WGA-HRP-labeled terminals were GABA positive. Quantification of these GABA/WGA-HRP-double-labeled terminals showed that 1) 30% of the GABAergic terminals randomly selected from the entire neuropil were double-labeled, 2) 13% of the GABAergic terminals adjacent to perikarya were double-labeled, and 3) 34% of the GABAergic terminals strategically located next to both of the dendritic elements linked by a gap junction were double-labeled. Statistical analysis of the above data showed that significantly fewer GABAergic terminals adjacent to perikarya were double-labeled (P less than .001) than would be expected from the double-labeled proportion of the randomly selected GABAergic terminals. Following injection of WGA-HRP in the nucleus of Darkschewitsch, all WGA-HRP-labeled terminals were GABA-negative. Quantification of these terminals showed that 1) 26% of the randomly selected nonGABAergic terminals were WGA-HRP labeled, 2) 20% of the nonGABAergic terminals adjacent to perikarya were WGA-HRP labeled, and 3) 23% of the nonGABAergic terminals strategically located next to a gap junction were WGA-HRP labeled. No significant differences were found among these populations. Quantification of terminals of both groups of experiments mentioned above showed that GABAergic terminals composed 1) 38% of the randomly selected terminals, 2) 64% of the terminals apposed to perikarya, and 3) 53% of the terminals strategically located next to gap junctions. Statistical analysis of the above data showed that significantly more GABAergic terminals were located adjacent to perikarya (P less than .001) and strategically next to a gap junction (P less than .05) than would be expected from the random GABAergic innervation. The above findings of the GABAergic, cerebellar, and mesodiencephalic input are discussed with regard to their functional role in the neuronal circuitry of the ros

Afferent Pathways↗
PubMed1988

A new combination of WGA-HRP anterograde tracing and GABA immunocytochemistry applied to afferents of the cat inferior olive at the ultrastructural level.

In order to identify cerebellar terminals in the cat inferior olive which contain gamma-aminobutyric acid (GABA), a technique was developed combining anterograde transport of wheatgerm agglutinine-conjugated horseradish peroxidase (WGA-HRP) with gold-immunocytochemistry. With this technique both the HRP reaction product and the immunogold labelling can be visualized in a single ultrathin section. Our results suggest that most, if not all of the WGA-HRP-labelled cerebellar terminals in the rostral medial accessory olive (MAO) and the rostral principal olive (PO) are GABAergic. In an additional experiment the GABAergic innervation of the rostral MAO was studied in combination with WGA-HRP anterograde tracing from the rostral mesencephalon. In this case the WGA-HRP-labelled terminals were never found to be GABA-positive.

Animals↗
PubMed1987

Brainstem projections to lumbar motoneurons in rat--I. An ultrastructural study using autoradiography and the combination of autoradiography and horseradish peroxidase histochemistry.

In 11 rats the descending projections from the ventrolateral medullary medial reticular formation, the medullary raphe nuclei and the area of the nucleus coeruleus and subcoeruleus to lumbar motoneuronal cell groups were studied by means of electron microscopical autoradiography after [3H]leucine injections in the respective brainstem areas. The distribution of the transported radioactivity in the autoradiographs was determined using the circle method [Williams (1977), in Practical Methods in Electron Microscopy, Vol. 6, pp. 85-173] which showed that the vast majority of the silver grains was located over terminal profiles. In the motoneuronal cell groups six different types of terminals were distinguished. After injections in the ventrolateral medial reticular formation the majority of the silver grains was located over F-type terminal profiles while many fewer silver grains were found over S- and G-types. After injections in the raphe nuclei and the adjoining medial reticular formation approximately equal numbers of silver grains were found over F- and G-type terminals while fewer were found over S-type. A small proportion of silver grains was present over C-type terminals and only after injections in the ventrolateral medial reticular formation. After [3H]leucine injections in the area of the nucleus coeruleus and subcoeruleus the majority of silver grains were located over E- and S-type terminals whereas relatively few were located over F-type terminals. The E-type terminal, which has not been described before in the motoneuronal cell groups, is characterized by the fact that it contains relatively small vesicles and occasionally elongated or canaliculi-like structures. In the three groups of experiments approximately 40-50% of the labelled S- and F-type terminal profiles established synaptic contacts, but only approximately 10% of the labelled E- and G-type terminal profiles did so. In all cases these synaptic contacts were established mainly with proximal dendrites. In the autoradiographs some of the silver grains were concentrated into clusters. The vast majority of these clusters, consisting of six or more silver grains, were centred over terminal profiles. The differential distribution of these clusters over the different types of terminal profiles in the various experiments was roughly the same as found by means of the circle method. In two rats [3H]leucine injections in the ventrolateral medial reticular formation were combined with horseradish peroxidase injections in the ipsilateral hindleg muscles, resulting in retrograde labelling of the corresponding motoneurons as visualized by means of the tetramethyl benzidine incubation method.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1987

Brainstem projections to lumbar motoneurons in rat--II. An ultrastructural study by means of the anterograde transport of wheat germ agglutinin coupled to horseradish peroxidase and using the tetramethyl benzidine reaction.

The descending projections from the ventrolateral medial reticular formation to the lumbar motoneuronal cell groups were studied in rat at the ultrastructural level using the anterograde transport of wheat germ agglutinin coupled to horseradish peroxidase in combination with the chromogen tetramethyl benzidine. The tissue containing the horseradish peroxidase reaction products was processed for electron microscopy using the method of chemical dehydration. In the ultrathin sections of the lumbar motoneuronal cell groups reaction products were easily recognized by their electron-dense crystal-like structure. These crystals were mostly found in terminals (66%) and to a lesser extent in axons (10%) and dendrites (10%). In the lumbar motoneuronal cell groups six different types of terminals were distinguished. It was found that F-type terminal profiles most frequently contained crystals, whereas fewer S- and G-types did so. The various findings are basically the same as those of a similar ultrastructural autoradiographic study with [3H]leucine as a tracer, except for the labelling of dendrites, which is discussed. It is concluded that the horseradish peroxidase technique employed in the present study can be reliably used for anterograde tracing at the ultrastructural level. Its advantages and disadvantages in comparison with the electron microscopical autoradiographic technique are discussed.

Animals↗
PubMed1987

Brainstem projections to spinal motoneurons: an update.

1. The existence of direct projections to spinal motoneurons and interneurons from the raphe pallidus and obscurus, the adjoining ventral medial reticular formation and the locus coeruleus and subcoeruleus is now well substantiated by various anatomical techniques. 2. The spinal projections from the raphe nuclei and the adjoining medial reticular formation contain serotonergic and non-serotonergic fibres. These projections also contain various peptides, several of which are contained within the serotonergic fibres. Whether still other transmitter substances (e.g. acetylcholine) are present in the various descending brainstem projections to motoneurons remains to be determined. 3. The spinal projections from the locus coeruleus and subcoeruleus are mainly noradrenergic, but there also exists a non-noradrenergic spinal projection. 4. Pharmacological, physiological and behavioural studies indicate an overall facilitatory action of noradrenaline and serotonin (including several peptides) on motoneurons. This may lead to an enhanced susceptibility for excitatory inputs from other sources. 5. The brainstem areas in question receive an important projection from several components of the limbic system. This suggests that the emotional brain can exert a powerful influence on all regions of the spinal cord and may thus control both its sensory input and motor output.

Animals↗
PubMed1979

Electron microscopic identification of mammillary body terminals in the rat's AV thalamic nucleus by means of anterograde transport of HRP. A quantitative comparison with the EM degeneration and EM autoradiographic techniques.

A comparison has been made between the number of horseradish peroxidase (HRP)-labeled mammillary body terminals in the antero-ventral (AV) nucleus and the number of such terminals labeled with the electron microscopic (EM) autoradiographic [6] and EM degeneration technique [6]. With the antero-grade HRP technique less terminals were labeled than with the autoradiographic technique, but more than with the degeneration technique. Furthermore it may be concluded that the anterograde HRP technique is suitable for determining the type of terminal and does not require the long exposure time of the autoradiographic technique.

Animals↗