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C R Gerfen

Publications and source records attributed to C R Gerfen.

At least 55 records · Page 3Linked to original sources
PubMed1991

Substance P (neurokinin-1) receptor mRNA is selectively expressed in cholinergic neurons in the striatum and basal forebrain.

In the striatum substance P (neurokinin-1) receptor, mRNA is selectively localized in large neurons that also express mRNA encoding choline acetyltransferase (ChAT) by in situ hybridization histochemistry. Substance P receptor mRNA is also localized in ChAT mRNA-containing neurons in the medial septum and basal forebrain cell groups. Thus, in the rat forebrain the substance P receptor appears to be expressed selectively by cholinergic neurons. Striatal neurons that contain substance P also utilize gamma-aminobutyric acid (GABA) as a transmitter. These neurons make synaptic contact with striatal cholinergic neurons, which are shown here to express the substance P receptor, and with other GABAergic neurons in the striatum and substantia nigra, which express GABA receptors but not substance P receptors. This suggests that individual striatal neurons may differentially affect target neurons dependent on the receptors expressed by those target neurons.

Animals↗
PubMed1991

Levodopa replacement therapy alters enzyme activities in striatum and neuropeptide content in striatal output regions of 6-hydroxydopamine lesioned rats.

The effects of striatal dopamine denervation and levodopa replacement therapy on neuronal populations in the rat striatum were assessed by measurement of glutamic acid decarboxylase (GAD) and choline acetyltransferase (CAT) activities in the striatum, dynorphin and substance P concentrations in the substantia nigra, and enkephalin concentration in the globus pallidus. Rats with a unilateral 6-hydroxydopamine (6-OHDA) lesion of the nigrostriatal pathway were treated for 21 days with levodopa (100 mg/kg/day, i.p., with 25 mg/kg benserazide) on either an intermittent (b.i.d.) or continuous (osmotic pump infusion) regimen and sacrificed following a three day drug washout. In saline-treated control rats, striatal GAD activity and globus pallidus enkephalin content were elevated and nigral substance P content was reduced ipsilateral to the 6-OHDA lesion. Intermittent levodopa treatment further increased GAD activity, decreased CAT activity, restored substance P to control levels, markedly increased dynorphin content, and had no effect on enkephalin. In contrast, continuous levodopa elevated globus pallidus enkephalin beyond the levels occurring with denervation, but had no effect on any of the other neurochemical measures. These results indicate that striatal neuronal populations are differentially affected by chronic levodopa therapy and by the continuous or intermittent nature of the treatment regimen. With the exception of substance P, levodopa did not reverse the effects of the 6-OHDA lesion but, rather, either exacerbated the lesion-induced changes (e.g. GAD and enkephalin) or altered neurochemical markers which had been unaffected by the lesion (e.g. CAT and dynorphin).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Dopamine differentially regulates dynorphin, substance P, and enkephalin expression in striatal neurons: in situ hybridization histochemical analysis.

Dopamine regulation of the levels of dynorphin, enkephalin, and substance P messenger RNAs in rat striatal neurons was analyzed with in situ hybridization histochemistry (ISHH). Relative levels of peptide mRNA expression in the patch and matrix compartments of the dorsolateral striatum were compared among control rats, rats treated for 10 d with apomorphine, rats with unilateral 6-hydroxydopamine (6-OHDA) lesions of the nigrostriatal dopaminergic system, and rats with nigrostriatal dopaminergic lesions followed 2 weeks later by 10 d of apomorphine treatment. Image analysis of ISHH labeling demonstrated that the number of neurons expressing each peptide mRNA remained constant, whereas the relative level of peptide mRNA per neuron changed significantly, depending on the experimental treatment. Dynorphin mRNA expression increased following chronic apomorphine treatment: striatal patch neurons increased to an average of 100% above control values, whereas striatal matrix neurons showed only a 25% increase. Dynorphin mRNA expression decreased following 6-OHDA lesions: patch neurons showed an average 75% reduction in expression, whereas matrix neurons showed no significant change. In animals with 6-OHDA lesions followed by apomorphine treatment, both patch and matrix neurons showed an average increase in dynorphin expression of 300% above control levels. Changes in dynorphin mRNA levels with these treatments were matched by qualitative changes in dynorphin immunoreactivity both in the striatum and in striatonigral terminals in the substantia nigra. Neither substance P nor enkephalin mRNA levels showed a significant difference between the striatal patch and matrix compartments in any experimental condition (in the dorsolateral striatum). Substance P mRNA expression was increased an average of 50% after 10 d of apomorphine treatment and showed an average decrease of 75% following 6-OHDA lesions of the mesostriatal system. There was no significant change in the expression of substance P mRNA in striatal neurons compared to control values in rats with combined 6-OHDA lesion and apomorphine treatment. Enkephalin mRNA expression was not significantly altered by chronic apomorphine treatment but showed an average increase per cell of some 130% above control levels following 6-OHDA-induced lesions of the mesostriatal system. In animals with a 6-OHDA lesion and apomorphine treatment, enkephalin mRNA was also elevated but not significantly above the levels produced by the lesions alone. These data show that the expression of dynorphin, enkephalin, and substance P is differentially regulated by the mesostriatal dopaminergic system and, further, suggests that the mechanisms by which this regulation occurs may be different for the 3 peptide families.

Animals↗
PubMed1991

Cloning and expression of an A1 adenosine receptor from rat brain.

We have used the polymerase chain reaction technique to selectively amplify guanine nucleotide-binding regulatory protein (G protein)-coupled receptor cDNA sequences from rat striatal mRNA, using sets of highly degenerate primers derived from transmembrane sequences of previously cloned G protein-coupled receptors. A novel cDNA fragment was identified, which exhibits considerable homology to various members of the G protein-coupled receptor family. This fragment was used to isolate a full-length cDNA from a rat striatal library. A 2.2-kilobase clone was obtained that encodes a protein of 326 amino acids with seven transmembrane domains, as predicted by hydropathy analysis. Stably transfected mouse A9-L cells and Chinese hamster ovary cells that expressed mRNA for this clone were screened with putative receptor ligands. Saturable and specific binding sites for the A1 adenosine antagonist [3H]-1,3-dipropyl-8-cyclopentylxanthine were identified on membranes from transfected cells. The rank order of potency and affinities of various adenosine agonist and antagonist ligands confirmed the identity of this cDNA clone as an A1 adenosine receptor. The high affinity binding of A1 adenosine agonists was shown to be sensitive to the nonhydrolyzable GTP analog guanylyl-5'-imidodiphosphate. In adenylyl cyclase assays, adenosine agonists inhibited forskolin-stimulated cAMP production by greater than 50%, in a pharmacologically specific fashion. Northern blot and in situ hybridization analyses of receptor mRNA in brain tissues revealed two transcripts of 5.6 and 3.1 kilobases, both of which were abundant in cortex, cerebellum, hippocampus, and thalamus, with lower levels in olfactory bulb, striatum, mesencephalon, and retina. These regional distribution data are in good agreement with previous receptor autoradiographic studies involving the A1 adenosine receptor. We conclude that we have cloned a cDNA encoding an A1 adenosine receptor linked to the inhibition of adenylyl cyclase activity.

Amino Acid Sequence↗
PubMed1990

D1 and D2 dopamine receptor-regulated gene expression of striatonigral and striatopallidal neurons.

The striatum, which is the major component of the basal ganglia in the brain, is regulated in part by dopaminergic input from the substantia nigra. Severe movement disorders result from the loss of striatal dopamine in patients with Parkinson's disease. Rats with lesions of the nigrostriatal dopamine pathway caused by 6-hydroxydopamine (6-OHDA) serve as a model for Parkinson's disease and show alterations in gene expression in the two major output systems of the striatum to the globus pallidus and substantia nigra. Striatopallidal neurons show a 6-OHDA-induced elevation in their specific expression of messenger RNAs (mRNAs) encoding the D2 dopamine receptor and enkephalin, which is reversed by subsequent continuous treatment with the D2 agonist quinpirole. Conversely, striatonigral neurons show a 6-OHDA-induced reduction in their specific expression of mRNAs encoding the D1 dopamine receptor and substance P, which is reversed by subsequent daily injections of the D1 agonist SKF-38393. This treatment also increases dynorphin mRNA in striatonigral neurons. Thus, the differential effects of dopamine on striatonigral and striatopallidal neurons are mediated by their specific expression of D1 and D2 dopamine receptor subtypes, respectively.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗
PubMed1990

Mechanisms of striatal pattern formation: conservation of mammalian compartmentalization.

The striatum is composed of two neuroanatomically and neurochemically defined compartments, termed the patches and matrix. We compared this compartmentalization of the striatum in sections from the rat, rhesus monkey and human, in terms of (1) total striatal area, (2) the ratio of patch to matrix areas, (3) the number of patches and (4) the cross-sectional area of individual patches. Dense mu-opiate receptor binding and immunohistochemical staining for enkephalin were used as histochemical markers for the patch compartment and heavy immunostaining for calcium binding protein was used as a matrix marker. Analysis of coronal sections revealed that a relatively constant ratio of 15% patch to 85% matrix area is maintained in each species. The numbers of patches also remain relatively constant across species, despite a 19-fold increase in total striatal area from rat to human. The constant ratio of patch to matrix areas is maintained by an increase in the size of the individual patches. We hypothesize that the maintenance of a 15% patch to 85% matrix ratio in the striata of different mammalian species occurs through proportionate changes in the length of striatal neurogenesis and the numbers of striatal precursors in the ventricular zone, whereas the maintenance of average patch number is proposed to be a function of reciprocal connections with the substantia nigra and adhesive factors that are specific to patch cells.

Animals↗
PubMed1990

Molecular cloning and expression of a D1 dopamine receptor linked to adenylyl cyclase activation.

In order to clone the D1 dopamine receptor linked to adenylyl cyclase activation, the polymerase chain reaction was used with highly degenerate primers to selectively amplify a cDNA sequence from NS20Y neuroblastoma cell mRNA. This amplification produced a cDNA fragment exhibiting considerable sequence homology to guanine nucleotide-binding (G)-protein-coupled receptors that have been cloned previously. To characterize this cDNA further, a full-length clone was isolated from a rat striatal library by using the cDNA fragment as a probe. Sequence analysis of this cDNA clone indicated that it is indeed a member of the G-protein-coupled receptor family and exhibits greatest homology with the previously cloned catecholamine receptors. Northern blot analysis of various neural tissues revealed a transcript of approximately 4 kb that was predominantly located in the striatum with lesser amounts in the cortex and retina. In contrast, no mRNA was detected in the cerebellum, hippocampus, olfactory bulb, mesencephalon, or pituitary. In situ hybridization analysis also revealed a high abundance of mRNA in the striatum as well as in the olfactory tubercle. To establish the identity of this cDNA, we performed transient expression experiments in COS-7 cells. [3H]SCH-23390, a D1-selective radioligand, exhibited specific, saturable binding only in cells that were transfected with this cDNA. Competition binding analysis with a variety of dopaminergic ligands demonstrated a D1 dopaminergic pharmacology. In addition, dopamine as well as other D1-selective agonists stimulated cAMP accumulation in transfected COS-7 cells. We conclude that we have cloned a cDNA encoding the D1 dopamine receptor linked to the activation of adenylyl cyclase activity.

Adenylyl Cyclases↗
PubMed1989

Compartmental organization of the ventral striatum of the rat: immunohistochemical distribution of enkephalin, substance P, dopamine, and calcium-binding protein.

In the caudate-putamen of the rat a patch/matrix organization can be recognized on the basis of the immunohistochemical distribution of several markers, which include enkephalin, substance P, dopamine, and calcium-binding protein. In the present experiments the distributional relations of these markers were investigated in the nucleus accumbens. The distribution of enkephalin fibers shows different inhomogeneities according to their location in the nucleus. Rostrally, heavily labeled areas stand out against a moderately stained background, whereas caudally, in medial and ventral parts of the nucleus, lightly stained areas delineate regions in the moderately stained neuropil. In the distribution of substance P, areas with high staining intensity were observed in the medial and ventral parts of the nucleus accumbens. Inhomogeneities in the distribution of strong dopamine immunoreactivity consist of weakly immunoreactive areas throughout the rostrocaudal extent of the nucleus accumbens and extremely heavily labeled areas in the medial and ventral parts of the nucleus. Calcium-binding protein immunoreactivity can only be detected in dorsal parts of the nucleus. The generally intense immunostaining for calcium-binding protein is interspersed with "blanks" of weak immunoreactivity. The heavily and moderately labeled enkephalin areas each maintain specific relations with inhomogeneities in the distribution of substance P, dopamine, and calcium-binding protein. Rostrally, the heavily labeled enkephalin areas coincide with areas strongly immunostained for calcium-binding protein and with lightly stained areas in the dopamine and substance P immunoreactivity patterns. In the same region lightly stained areas in the enkephalin distribution match heavily labeled substance P areas. Caudally, in the border region of the nucleus accumbens and the caudate-putamen, the heavily labeled enkephalin areas are either related to "blanks" or to the intense staining regions in the calcium-binding protein immunoreactivity distribution. The moderately labeled enkephalin areas caudomedially in the nucleus accumbens are in register with the heavily labeled regions in the distribution of substance P and with the extremely heavily labeled regions in the distribution of dopamine. Relations with connectivity are discussed and the inhomogeneities are compared to those in the caudate-putamen. It is concluded that in the ventral striatum either one patch and one matrix compartment exist with different immunohistochemical relationships or there are several compartments with different immunohistochemical characteristics and different input-output relations.

Animals↗
PubMed1989

The neostriatal mosaic: striatal patch-matrix organization is related to cortical lamination.

The basal ganglia, of which the striatum is the major component, process inputs from virtually all cerebral cortical areas to affect motor, emotional, and cognitive behaviors. Insights into how these seemingly disparate functions may be integrated have emerged from studies that have demonstrated that the mammalian striatum is composed of two compartments arranged as a mosaic, the patches and the matrix, which differ in their neurochemical and neuroanatomical properties. In this study, projections from prefrontal, cingulate, and motor cortical areas to the striatal compartments were examined with the Phaseolus vulgaris-leucoagglutinin (PHA-L) anterograde axonal tracer in rats. Each cortical area projects to both the patches and the matrix of the striatum; however, deep layer V and layer VI corticostriatal neurons project principally to the patches, whereas superficial layer V and layer III and II corticostriatal neurons project principally to the matrix. The relative contribution of patch and matrix corticostriatal projections varies among the cortical areas examined such that allocortical areas provide a greater number of inputs to the patches than to the matrix, whereas the reverse obtains for neocortical areas. These results demonstrate that the compartmental organization of corticostriatal inputs is related to their laminar origin and secondarily to the cytoarchitectonic area of origin.

Animals↗
PubMed1988

Distribution of striatonigral and striatopallidal peptidergic neurons in both patch and matrix compartments: an in situ hybridization histochemistry and fluorescent retrograde tracing study.

In situ hybridization histochemistry using cDNA oligonucleotide probes for the neuropeptides dynorphin, enkephalin and substance P was used to map the distribution of peptidergic neurons in the striatal patch and matrix compartments in the rat. Striatal neurons containing message for each of these peptides were distributed in both striatal compartments in the following proportions: dynorphin, in 52% of patch neurons and 45% of matrix neurons; enkephalin, in 65% of patch neurons and 58% of matrix neurons and substance P, in 61% of patch neurons of 54% matrix neurons. Fluorescent retrograde axonal tracing combined with in situ hybridization histochemistry demonstrated that the majority of neurons expressing enkephalin project to the globus pallidus and few project to the substantia nigra, whereas the reverse obtains for neurons expressing dynorphin and substance P.

Animals↗
PubMed1988

Calcium binding protein in the basal ganglia system of a non-mammalian vertebrate: an immunohistochemical study in the reptile Caiman crocodilus.

In Caiman, calbindin D28K immunoreactivity (CaBP) was observed within many neurons of the substantia nigra (SN) but only in the caudal portion of the area ventralis of Tsai (AVT). A dense CaBP fiber plexus showing some regional inhomogeneity was observed in the dorsolateral portion of the telencephalic ventrolateral area (VLA). These results are consistent with previous reports that the SN and AVT project to the dorsolateral and medial portions of the VLA, and strongly support the theory that the caiman VLA contains cell populations homologous to those found in the mammalian corpus striatum.

Alligators and Crocodiles↗
PubMed1988

Synaptic organization of the striatum.

The striatum, the main component of the basal ganglia, is composed of mainly one type of neuron, the so-called medium spiny neuron. This neuron cell type, which constitutes over 90% of striatal neurons, is the major output neuron of the striatum. Combined ultrastructural neuroanatomical methods have elucidated the organization of afferent connectivity to these neurons. The major physiologic function of striatal efferent activity appears to be inhibition of tonically active GABAergic neurons in the globus pallidus and substantia nigra pars reticulata. Thus, the excitatory input from the cerebral cortex, whose afferents make asymmetric synapses with the spines of medium spiny neurons, appears to drive the efferent activity of the striatum. Other extrinsic and intrinsic afferent synapses are situated in a position to regulate the effect of the corticostriatal excitatory input to the medium spiny neurons. For example, dopaminergic afferents from the midbrain make mainly symmetric synapses with the spine necks and dendritic shafts of the medium spiny neurons. Medium spiny neurons themselves have local axon collaterals, in addition to their efferent axon that exits the striatum, which serve to link together local clusters of medium spiny neurons. These local axon collaterals, which contain either GABA, substance P, or enkephalin, also make mainly symmetric synapses with the necks of spines or dendritic shafts of medium spiny neurons. Other afferents with similar synaptic connections to these neurons arise from cholinergic or somatostatinergic striatal intrinsic neurons. Additionally, the patterns of extrinsic and intrinsic afferents to medium spiny neurons and their extrinsic projections are related to the organization of medium spiny neurons into two mosaically organized macroscopic compartments, the striatal patches and matrix.

Animals↗
PubMed1988

Phospholipase C I and II brain isozymes: immunohistochemical localization in neuronal systems in rat brain.

Two distinct inositol phospholipid-specific phospholipase C (PLC; phosphatidylcholine phosphatidohydrolase, EC 3.1.4.3) isozymes, PLC-I and PLC-II, have been purified and characterized from bovine brain. Monoclonal antibodies that distinguish between these isozymes are used in the present study to map isozyme distribution in the rat brain with immunohistochemical techniques. Both isozymes are localized in neurons, and, whereas PLC-II is rather ubiquitous--being expressed in most neurons, PLC-I is restricted in its distribution. The strongest immunoreactive labeling for PLC-I is in the neurons of the striatum, which provide inputs to the globus pallidus and substantia nigra, where terminals are also densely labeled. The neuronal targets of these terminals in the globus pallidus and substantia nigra do not express PLC-I immunoreactivity, but they do display PLC-II immunoreactivity. PLC-I immunoreactivity is also particularly well pronounced in the pyramidal cells of the hippocampus and, to a lesser extent, in the granule cells of the dentate gyrus. In the thalamus, PLC-I is localized to neurons in the reticular thalamic nucleus, in the medial subdivision of the mediodorsal thalamic nucleus, and in the anteromedial thalamic nucleus. Other areas displaying PLC-I immunoreactive neurons include the dorsal lateral septal nucleus and the basolateral amygdala. The expression of at least one or more forms of PLC in most neurons of the brain suggests that this enzyme may be part of a common system of signal transduction used universally by all neurons. However, the differential expression of PLC isozymes suggests further that certain neurotransmitter and receptor interactions may differ in the forms of the PLC enzyme used for signal transduction.

Animals↗
PubMed1987

Differential distribution of signal-transducing G-proteins in retina.

We used specific antibodies in immunoblot studies of membrane fractions derived from bovine retina, and in immunohistochemical studies of sections of rat retina to determine the distribution of two guanine nucleotide binding proteins Go (a G-protein of unknown function discovered in the brain) and transducin, in retina. Both Go and transducin were readily detected in membranes derived from whole retina, and in crude rod outer segment membranes. Purification of rod outer segment membranes by sucrose density gradient centrifugation resulted in enrichment in transducin and depletion of Go immunoreactivity. Transducin-alpha immunoreactivity was localized to photoreceptor inner and outer segments and the outer nuclear layer. In contrast, Go-alpha immunoreactivity was localized in the inner and outer plexiform layers and ganglion cell layer. The results indicate that Go unlike transducin, is not associated with rod outer segment membranes and is therefore unlikely to function in phototransduction. Go is, however, relatively abundant in neural layers of retina where it may be involved in signal transduction.

Animals↗
PubMed1987

The neostriatal mosaic: II. Patch- and matrix-directed mesostriatal dopaminergic and non-dopaminergic systems.

Mesostriatal projections, which arise from dopaminergic and non-dopaminergic neurons in the ventral tegmental area, substantia nigra, and retrorubral area, are compartmentally organized in the striatum. Anterograde axonal tract tracing with Phaseolus vulgaris-leucoagglutinin (PHA-L), combined with immunohistochemical localization of tyrosine hydroxylase (TH) and autoradiographic localization of mu-opiate receptor binding sites, shows that midbrain projections to the striatum are distributed to either the mu-opiate receptor-rich "patch" or the receptor-poor "matrix" striatal compartments. Three morphologically distinct mesostriatal afferent fiber types are labeled. The first type, type A, forms a plexus of relatively thin (0.1-0.4 micron), smooth fibers with small varicosities (0.3-0.6 micron). A second type, type B, is similar to the first in forming a plexus of fibers, but is slightly thicker (0.2-0.6 micron), with more frequent varicosities (0.4-1.0 micron) that give this fiber type a crinkled appearance. The third type, type C, constitutes a minority of striatal afferents and is characterized by its large caliber (0.4-0.7 micron) with large bulbous varicosities (1.2-2.0 micron). Projections of the ventral tegmental area (A10 cell group) are primarily dopaminergic type A fibers directed to the matrix of the ventromedial striatum, including the nucleus accumbens. The retrorubral area (A8 cell group) also provides predominantly dopaminergic type A fibers to the striatal matrix, but these are distributed dorsally. The substantia nigra contains a mixed population of neurons that project to the striatum. Some, located in the dorsal tier of the pars compacta (dorsal A9 cell group), provide dopaminergic type A fibers to the striatal matrix. Others, in the ventral tier of the pars compacta (ventral A9 cell group) and in the ventral tier of the pars reticulata (displaced A9 cells), provide dopaminergic type B fibers to the striatal patches. An additional set of substantia nigra neurons that are non-dopaminergic is the source of type C fibers to the striatal matrix. Thus, distinct dorsal and ventral sets of midbrain dopaminergic neurons project, respectively, to striatal matrix and patches, and there is a non-dopaminergic mesostriatal projection to the matrix.

Afferent Pathways↗
PubMed1987

The neostriatal mosaic: III. Biochemical and developmental dissociation of patch-matrix mesostriatal systems.

In the previous paper (Gerfen et al., 1987) mesostriatal dopaminergic neurons were shown to be subdivided into dorsal and ventral tiers that project to the striatal matrix and patch compartments, respectively. The present study provides experimental evidence that these patch-matrix mesostriatal dopaminergic systems are biochemically and developmentally distinct. A 28 kDa calcium-binding protein (CaBP, or calbindin-D28 kDa) is expressed in dorsal tier mesostriatal dopaminergic neurons. The distribution of such neurons, located in the ventral tegmental area, dorsal tier of the substantia nigra pars compacta, and retrorubral area, matches that of dopaminergic neurons that project to the striatal matrix. Dopaminergic neurons that do not express CaBP--those in the ventral tier of the pars compacta and in the pars reticulata--are distributed in a pattern that matches the origin of the dopaminergic projection to the striatal patches. During development, dopaminergic afferents to the striatal patch compartment are in place prior to the development of those to the matrix. Injections of the neurotoxin 6-hydroxydopamine (6-OHDA) into the striatum of newborn rats result in a selective and long-lasting depletion of dopaminergic afferents in the striatal patches. The later-developing matrix projection is relatively spared by such lesions. The distribution of surviving dopaminergic neurons, labeled with tyrosine hydroxylase (TH) immunoreactivity, matches the pattern of dorsal tier neurons previously shown to provide inputs to the matrix. Surviving neurons also express CaBP immunoreactivity and have dendrites that spread mediolaterally, in the plane of the pars compacta. On the other hand, those neurons that project to the patches are selectively lesioned by the neonatal 6-OHDA striatal injections, do not express CaBP, and have dendrites that are directed ventrally into the pars reticulata.

Animals↗
PubMed1985

A method for anterograde axonal tracing of chemically specified circuits in the central nervous system: combined Phaseolus vulgaris-leucoagglutinin (PHA-L) tract tracing and immunohistochemistry.

A method is described for combining anterograde axonal tract tracing using concurrent double immunohistochemical localization of axonally transported Phaseolus vulgaris-leucoagglutinin (PHA-L) and endogenous neural antigens. With this technique, some projections of the substantia nigra and the paraventricular hypothalamic nucleus are examined to demonstrate advantages offered by this approach for tracing chemically specified circuits in the central nervous system.

Animals↗