Biomedical subjects

D R Sengelaub

Publications and source records attributed to D R Sengelaub.

At least 19 recordsLinked to original sources

PubMed2007

Androgen regulates trkB immunolabeling in spinal motoneurons.

Neurotrophic factors and steroid hormones have been shown to have neuroprotective/neurotherapeutic effects, and it has been shown previously that brain-derived neurotrophic factor (BDNF) and testosterone have a combinatorial effect in the maintenance of motoneurons. Given that gonadal hormones regulate the BDNF receptor, tyrosine receptor kinase B (trkB), we hypothesized that such a regulatory effect could mediate the interactive effects of BDNF and testosterone. Using immunohistochemical methods, we examined the frequency of cells immunolabeled for trkB receptors in two populations of spinal motoneurons, the hormone-sensitive, sexually dimorphic motoneurons of the spinal nucleus of the bulbocavernosus (SNB) and the nondimorphic motoneurons innervating the muscles of the quadriceps. In both the highly androgen-sensitive SNB motoneurons and the more typical somatic motoneurons innervating the quadriceps, the frequency of motoneurons intensely immunolabeled for trkB receptors was regulated by the presence of testosterone. Castrated animals deprived of testosterone showed a reduced frequency of intensely labeled motoneurons compared with intact animals or castrated animals given testosterone replacement. This finding suggests that the combinatorial effect of BDNF and testosterone in the maintenance of motoneurons could occur at least in part through an androgen-mediated expression of the BDNF receptor.

Androgens↗

PubMed2003

Brain-derived neurotrophic factor and androgen interact in the maintenance of dendritic morphology in a sexually dimorphic rat spinal nucleus.

Testosterone regulates androgen receptor expression, soma size, and dendritic length in motoneurons of the spinal nucleus of the bulbocavernosus (SNB) in adult male rats. Brain-derived neurotrophic factor (BDNF) is also expressed in SNB motoneurons; BDNF maintains SNB soma size in castrates, and interacts with testosterone to regulate androgen receptor expression in SNB motoneurons. This study tested the hypotheses that BDNF promotes SNB dendritic lengths and that BDNF and testosterone interact to maintain dendritic morphology in SNB motoneurons. Adult male rats were castrated; and, 5 wk later, SNB motoneurons were axotomized bilaterally, and BDNF or PBS was applied via cups sutured to the cut axons. After axotomy plus BDNF or PBS application, castrates received implants of testosterone or blank capsules and were killed 24 d later. Additional males of similar age that received sham castration, sham axotomy, and a blank implant served as sham controls. Two days before death, SNB motoneurons were retrogradely labeled with cholera toxin-horseradish peroxidase, and SNB dendritic morphology was reconstructed in three dimensions. Dendritic lengths in blank-implanted castrates treated with PBS were significantly shorter than those of sham controls; treatment with either testosterone or BDNF alone failed to support dendritic length or distribution. However, treatment with both testosterone and BDNF restored dendritic morphology to the level of sham controls. Our findings demonstrate that BDNF interacts with testosterone in the maintenance of SNB dendritic arbors and support the hypothesis that dendritic morphology is regulated by trophic substances that originate in the neuromuscular periphery.

Androgens↗

PubMed2002

Castration reduces motoneuron soma size but not dendritic length in the spinal nucleus of the bulbocavernosus of wild-type and BCL-2 overexpressing mice.

Motoneurons in the spinal nucleus of the bulbocavernosus (SNB) and their target muscles, bulbocavernosus and levator ani (BC/LA), constitute an androgen-sensitive neuromuscular system. Testosterone regulates SNB soma size, SNB dendritic length, and BC/LA muscle mass in adult male rats. Recent evidence indicates that the cell death-regulatory protein, Bcl-2, may also play a role in adult neural plasticity. The present study examined whether gonadal hormones and/or the Bcl-2 protein influence the morphology of the SNB neuromuscular system in adult B6D2F1 mice. In Experiment 1, adult wild-type and Bcl-2 overexpressing males were castrated and implanted with silastic capsules containing testosterone or left blank. Six weeks after castration, cholera toxin-horseradish peroxidase was injected into the BC muscle to label SNB dendrites. Animals were killed 48 h later, and BC/LA muscle mass, SNB soma size, and SNB dendritic arbors were examined. In Experiment 2, wild-type and Bcl-2 overexpressing males were castrated or sham castrated, implanted with testosterone-filled or blank capsules, and examined 12 weeks later. In both experiments, BC/LA muscle mass and SNB soma size were significantly reduced in castrates receiving blank capsules. Surprisingly, however, there was no effect of hormone manipulation on any of several measures of dendritic length. Thus, the dendritic morphology of SNB motoneurons appears to be relatively insensitive to circulating androgen levels in B6D2F1 mice. Bcl-2 overexpression did not influence BC/LA muscle mass, SNB soma size, or SNB dendritic length, indicating that the morphology of this neuromuscular system and the response to castration are not altered by forced expression of the Bcl-2 protein.

Animals↗

PubMed2002

Cultures, genes, and neurons in the development of song and singing in brown-headed cowbirds (Molothrus ater).

In brown-headed cowbirds, Molothrus ater, as in many songbird species, vocalizations are fundamental to reproduction. In our studies, experiments utilizing different social housing regimes and geographic comparisons have indicated the social learning of males' vocalizations and associated abilities to use vocalizations effectively during the breeding season. Here, we describe studies indicating roles of cultural and genetic background, and of social influences from females, on male vocal development. These influences can interact with neural regions, including song learning and song control nuclei, but also visual-processing nuclei, in the development of signaling. We argue that a developmental systems approach to the study of vocal behavior provides a structure to organize these different influences and how they may interact with one another over development. A systems approach requires that researchers study the social context in which signals and signalers develop - both the ontogenetic arena in which young animals learn their signals from older animals, and the functional arena in which young and older animals socially interact with one another.

Animals↗

PubMed2001

Ovariectomy attenuates dendritic growth in hormone-sensitive spinal motoneurons.

The lumbar spinal cord of rats contains the sexually dimorphic, steroid-sensitive spinal nucleus of the bulbocavernosus (SNB). Dendritic development of SNB motoneurons in male rats is biphasic, initially showing exuberant growth through 4 weeks of age followed by a retraction to mature lengths by 7 weeks of age. The initial growth is steroid dependent, attenuated by castration or aromatase inhibition, and supported by hormone replacement. Dendritic retraction is also steroid sensitive and can be prevented by testosterone treatment, but is unaffected by aromatase inhibition. Together, these results suggest a role for estrogens during the initial growth phase of SNB development. In this study, we tested whether ovarian hormones could support SNB somal and dendritic development. Motoneuron morphology was assessed in normal males and in females perinatally masculinized with dihydrotestosterone and then either ovariectomized or left intact. SNB motoneurons were retrogradely labeled with cholera toxin-HRP at 4 or 7 weeks of age and reconstructed in three dimensions. Initial growth of SNB dendrites was reduced after ovariectomy in masculinized females. However, no differences in dendritic length were seen at 7 weeks of age between intact and ovariectomized masculinized females, and lengths in both groups were significantly lower than those of normal males. Together with previous findings, these results suggest that estrogens are involved in the early growth of SNB dendrites, but not in their subsequent retraction.

Animals↗

PubMed1999

Estrogen receptor expression in the facial nucleus of adult hamsters: does axotomy recapitulate development?

Testosterone propionate (TP) augments hamster facial motoneuron regeneration following axonal injury by an androgen-mediated mechanism. Although many of the trophic properties of TP are androgenic, TP can be metabolized to estradiol (E). We have recently shown that E administered in supraphysiological doses can also enhance facial nerve regeneration. The mechanism by which E alters nerve regeneration is unknown. The recent discovery of transient estrogen receptor (ER) expression in the developing rat facial motor nucleus (FMN), coupled with the concept that regeneration may recapitulate development, has led to the hypothesis that facial nerve injury may transiently induce expression of ER in the adult hamster FMN or one of its chief afferents, the principal nucleus of the trigeminal nerve (Nu5). In the present study, this hypothesis was tested using steroid hormone autoradiographic procedures. The right facial nerve was injured in castrated or castrated plus TP adult hamsters. A gonadally intact, nonaxtomized group of hamsters was also included to examine constitutive expression of ER in the FMN or Nu5. The paraventricular nucleus of the hypothalamus (PVN; positive control), FMN, and Nu5, were qualitatively and quantitatively examined for the presence of ER. As expected, ER were present in the PVN-positive control in all groups. ER were neither present nor induced with facial nerve injury or TP administration in either the FMN or Nu5. Alternate mechanisms by which E enhancement of facial nerve regeneration without ER might be explained are discussed.

Animals↗

PubMed1999

Aromatase inhibition reduces dendritic growth in a sexually dimorphic rat spinal nucleus.

The rat lumbar spinal cord contains the steroid-sensitive spinal nucleus of the bulbocavernosus (SNB), whose motoneurons innervate perineal muscles involved in copulatory reflexes. In normal males, SNB motoneuron dendrites grow exuberantly through postnatal (P) day 28. This growth is steroid dependent: Dendrites fail to grow in males castrated at P7, but grow normally in castrates treated with testosterone or its metabolites, dihydrotestosterone combined with estrogen. Treatment with either metabolite alone supports dendritic growth, but not to the level of testosterone-treated or intact males. In this study, we tested the hypothesis that aromatization of androgens to estrogens was involved in the masculine development of SNB dendrites. Motoneuron morphology was assessed in normal males and males treated daily (P7-28) with fadrozole, a potent aromatase inhibitor (0.25 mg/kg, subcutaneously) or saline vehicle (n = 4-6/group). SNB motoneurons were retrogradely labeled with cholera toxin-horseradish peroxidase at P28 (when dendritic length is normally maximal) and reconstructed in three dimensions. Comparable labeling was seen across groups; it was equivalent in both the rostrocaudal and radial extents. However, dendritic lengths in fadrozole-treated males were significantly below those of intact or saline-treated males. Neither SNB somata size nor target muscle weight differed across groups. These results suggest that aromatization of androgens to estrogens is necessary for development of masculine SNB dendritic morphology.

Androgens↗

PubMed1998

CEP-1347/KT7515 prevents motor neuronal programmed cell death and injury-induced dedifferentiation in vivo.

CEP-1347, also known as KT7515, a derivative of a natural product indolocarbazole, inhibited motor neuronal death in vitro, inhibited activation of the stress-activated kinase JNK1 (c-jun NH terminal kinase) in cultured spinal motor neurons, but had no effect on the mitogen-activated protein kinase ERK1 in these cells. Results reported here profile the functional activity of CEP-1347/KT7515 in vivo in models of motor neuronal death or dedifferentiation. Application of CEP-1347/KT7515 to the chorioallantoic membrane of embryonic chicks rescued 40% of the lumbar motor neurons that normally die during the developmental period assessed. Peripheral administration of low doses (0.5 and 1 mg/kg daily) of CEP-1347/KT7515 reduced death of motor neurons of the spinal nucleus of the bulbocavernosus in postnatal female rats, with efficacy comparable to testosterone. Strikingly, daily administration of CEP-1347/KT7515 during the 4-day postnatal window of motor neuronal death resulted in persistent long-term motor neuronal survival in adult animals that received no additional CEP-1347/KT7515. In a model of adult motor neuronal dedifferentiation following axotomy, local application of CEP-1347/KT7515 to the transected hypoglossal nerve substantially reduced the loss of choline acetyl transferase immunoreactivity observed 7 days postaxotomy compared to untreated animals. Results from these experiments demonstrate that a small organic molecule that inhibits a signaling pathway associated with stress and injury also reduces neuronal death and degeneration in vivo.

Animals↗

PubMed1998

Prenatal gonadal steroids affect adult spatial behavior, CA1 and CA3 pyramidal cell morphology in rats.

The present study assessed whether prenatal androgen and estrogen exposure affected adult spatial learning and hippocampal morphology. Water maze performance, the CA1 and CA3 pyramidal cell field, and the dentate gyrus-granule cell layer (DG-GCL) morphology were assessed at adulthood (70+ days of age) in males, females, androgen-treated (testosterone propionate, TP, or dihydrotestosterone propionate, DHTP) females (2-4 mg/day), estradiol benzoate (EB)-treated females (100 microgram/day), and males treated with the antiandrogen flutamide (8 mg/day). Pregnant rats were injected daily (sc) between Embryonic Day 16 and birth; all pups were delivered by cesarean section. Flutamide-treated males were castrated upon delivery, and adult castrates were used to control for activational effects. Steroid-sensitive sex differences were observed in water maze performance in favor of males. Males had larger CA1 and CA3 pyramidal cell field volumes and soma sizes than females, which were feminized with flutamide treatment. TP and EB, but not DHTP, masculinized CA1 pyramidal cell field volume and neuronal soma size; CA3 was masculinized in both TP- and DHTP-treated females, while EB was ineffective. No effects were observed in cell density, number, or DG-GCL volume or due to adult hormone levels. Thus, prenatal androgens and estrogen influence sex differences in adult spatial navigation and exert differential effects on CA1 and CA3 pyramidal cell morphology. Hence, in addition to the previously reported postnatal component, there is also a prenatal component to the critical period in which gonadal steroids organize the neural mechanisms underlying sex differences in adult spatial ability.

Androgens↗

PubMed1997

Denervation-induced sprouting of intact peripheral afferents into the cuneate nucleus of adult rats.

In adult monkeys with dorsal rhizotomies extending from the second cervical (C2) to the fifth thoracic (T5) vertebrae, cortex deprived of its normal inputs regained responsiveness to inputs conveyed by intact peripheral afferents from the face [T.P. Pons, P.E. Garraghty, A.K. Ommaya, J.H. Kaas, E. Taub, M. Mishkin, Massive reorganization of the primary somatosensory cortex after peripheral sensory deafferentation, Science 252 (1991) 1857-1860]. It has been suggested that the extent of this massive topographic reorganization may be due to the establishment of novel connections between intact afferents and neurons denervated after dorsal rhizotomy [P.E. Garraghty, D.P. Hanes, S.L. Florence, J.H. Kaas, Pattern of peripheral deafferentation predicts reorganizational limits in adult primate somatosensory cortex, Somatosens. Motor Res. 11 (1994) 109-117]. Using adult rats with comparably extensive dorsal rhizotomies, we employed anatomical tracing techniques to address this possibility. Subcutaneous hindpaw injections of horseradish peroxidase conjugated to either wheat germ agglutinin or cholera toxin subunit B revealed aberrant expansions of gracile projections into the cuneate and, in one case, external cuneate nucleus within three months of the deafferentation. It seems plausible that such modest sprouting of ascending projections at the level of the brainstem may form functional connections which, through divergence, ultimately drive a larger population of neurons in cortex. This new growth may well account for both the substantial cortical reorganization observed in the 'Silver Spring monkeys' [T.P. Pons, P.E. Garraghty, A.K. Ommaya, J.H. Kaas, E. Taub, M. Mishkin, Massive reorganization of the primary somatosensory cortex after peripheral sensory deafferentation, Science 252 (1991) 1857-1860] and the 'referred sensation' phenomena (see J.P. Donoghue, Plasticity of adult sensorimotor representations, Curr. Opin. Neurobiol., 5 (1995) 749-754 for review) reported to follow proximal limb amputations in humans.

Afferent Pathways↗

PubMed1997

Synergistic effects of testosterone metabolites on the development of motoneuron morphology in a sexually dimorphic rat spinal nucleus.

The rat lumbar spinal cord contains the testosterone-dependent spinal nucleus of the bulbocavernosus (SNB), whose motoneurons innervate perineal muscles involved in copulatory reflexes. In normal males, SNB dendrites grow exuberantly through the first 4 weeks postnatally. This growth is steroid-dependent: dendrites fail to grow in males castrated at P7, but grow normally in castrates treated with testosterone (T). Treatment with either of the T metabolites, dihydrotestosterone or estrogen, supports dendritic growth in castrates, but not to the lengths characteristic of intact males or T-treated castrates. The present study tested the hypothesis that dihydrotestosterone and estrogen act together to support development of SNB dendrites. Male rat pups were castrated on P7 and treated daily with dihydrotestosterone propionate (DHT) (2 mg), estradiol benzoate (E) (100 microg), DHT (2 mg) combined with estradiol benzoate in either 5 microg (E5) or 100 microg (E100) doses, or vehicle alone. On P28, when SNB dendritic length is normally maximal, motoneurons were retrogradely labeled with cholera toxin-HRP (BHRP). Soma size and dendritic lengths of labeled motoneurons were assessed and compared to those of age-matched, intact male rats. Soma areas of DHT + E5-treated and DHT + E100-treated castrates did not differ from those of castrates treated with DHT alone, although somata of all three groups were significantly larger than those of normal males and E- or oil-treated castrates. Dendritic lengths in DHT + E5-treated castrates were significantly shorter than those of normal males, and did not differ from those of castrates receiving DHT or E alone, although all hormone-treated groups had dendritic lengths that were significantly longer than untreated castrates. However, treatment of castrates with DHT + E100 fully supported dendritic growth to levels characteristic of normal males. These results suggest that somal and dendritic growth may occur through separate developmental mechanisms, and that E and DHT act synergistically to support normal masculine SNB dendritic development.

Animals↗

PubMed1997

A brain of her own: a neural correlate of song assessment in a female songbird.

The song control region in the avian forebrain is a series of discrete, interconnected nuclei mediating song learning and production. It has been studied in males or in species where both sexes sing. Little is known about the neural correlates of song perception in nonsinging females, often the intended recipients of song. We studied cowbirds (Molothrus ater), a species in which only males sing but in which females discriminate between males on the basis of song. We focused on nucleus lMAN because it has been implicated in early song acquisition, a stage relevant to both sexes to choose among competing acoustic models. We found that volume of lMAN was monomorphic in cowbirds. Moreover, the volume and neuronal number of female lMAN were positively correlated with selectivity of copulatory responding. The results provide strong evidence of nonsinging female's use of "song" control nuclei for song perception without the possibility of song production.

Animal Communication↗

PubMed1996

Motoneuron development after deafferentation. I. dorsal rhizotomy does not alter growth in the spinal nucleus of the bulbocavernosus (SNB).

The spinal nucleus of the bulbocavernosus (SNB) and the dorsolateral nucleus (DLN) are sexually dimorphic motor nuclei in the rat lumbar spinal cord. During postnatal development, SNB and DLN motoneurons grow substantially in measures of soma size, dendritic length, and radial dendritic extent. SNB motoneurons exhibit a biphasic pattern of dendritic growth, where there is an initial period of exuberant growth followed by a period of retraction to mature lengths by 7 weeks. In this experiment, we examined whether primary afferent input to the SNB nucleus was necessary for the normal postnatal growth of SNB motoneurons. We partially deafferented the SNB via unilateral dorsal rhizotomy of lumbosacral dorsal roots in male rats at 1 week of age. Using cholera toxin horseradish peroxidase (BHRP) to visualize SNB motoneurons, we examined SNB motoneuron morphology at 4 and 7 weeks of age. SNB motoneurons in rhizotomized males developed normally; measures of dendritic length in rhizotomized males were typically exuberant at 4 weeks of age, and declined significantly to mature lengths by 7 weeks of age. In addition, dorsal rhizotomy did not alter the development of SNB motoneuron soma size or radial dendritic extent. These results are discussed in reference to sensorimotor connections in the SNB, the extent of the deafferentation, and dendrodendritic interactions.

Animals↗

PubMed1996

Motoneuron development after deafferentation: II. dorsal rhizotomy does not block estrogen-supported growth in the dorsolateral nucleus (DLN).

The lumbar spinal cord of the rat contains two sexually dimorphic motor nuclei, the spinal nucleus of the bulbocavernosus (SNB) and the dorsolateral nucleus (DLN). Postnatally, SNB and DLN motoneurons grow substantially and reach their adult morphology by 7 weeks of age. The masculinization of SNB and DLN motoneuron dendrites depends upon steroid hormones. After early castration, the growth of SNB and DLN dendrites is markedly attenuated, but testosterone replacement restores this growth. In the SNB, initial dendritic growth is also supported in castrates treated with estrogen. By using castration and hormone replacement techniques, we examined the development of DLN motoneuron morphology in estrogen-treated castrated rats to determine if estrogen also supports the growth of DLN motoneurons. In addition, given that dorsal root ganglia may be a site of estrogen action, we tested the hypothesis that estrogen acts at primary afferents to support DLN dendritic growth. Thus, we attempted to block the potential trophic effect of estrogen by performing unilateral dorsal rhizotomies in estrogen-treated castrates. DLN motoneuron morphology was analyzed at 4 and 7 weeks of age by using cholera toxin horseradish peroxidase (BHRP) histochemistry. As found for SNB motoneurons, estrogen treatment transiently supported development. DLN motoneurons in estrogen-treated castrates developed normally through 4 weeks of age, but by 7 weeks, DLN motoneuron morphology in estrogen-treated castrates was no longer different from that in oil-treated castrates. Moreover, deafferentation via unilateral dorsal rhizotomy did not inhibit estrogen's ability to masculinize the early development of DLN motoneurons. Thus, the trophic effect of estrogen did not appear to act via the dorsal root ganglia to support the early postnatal development of DLN motoneurons.

Animals↗

PubMed1995

Alterations in dendritic morphology of frontal cortical neurons after basal forebrain lesions in adult and aged rats.

The nucleus basalis magnocellularis (NBM) is the major cholinergic projection to neocortex in the rat and plays a role in the modulation of cortical activity. Lesions of the NBM decrease thickness of lamina II-III of frontal cortex and decrease soma size of lamina II-III neurons. Additionally, aging produces changes in neuron size and numbers in the basal forebrain and frontal cortex of rats. We assessed dendritic changes in neurons from lamina II-III of frontal cortex in adult, middle-aged, and aged rats three months after unilateral lesions of the NBM. While lesions did not affect dendritic morphology in young adult rats, they decreased total dendritic length in middle-aged and aged rats, with dendritic alterations most pronounced in middle-aged rats. In middle-aged rats, lesion-induced changes in basilar arbor were apparently due to decreased dendritic branching: lesions markedly decreased the number of first-, second-, and third-order branches, but did not affect higher-order branching. In aged rats, lesions resulted in a small decrease in dendritic material proximal to the soma and a pronounced decrease in dendritic material distal to the soma, apparently due to a decrease in the length of terminal branches. These results suggest that the plasticity of neocortical neurons in the basalocortical system changes with age, and that early in aging this system may be particularly vulnerable to neural damage.

Age Factors↗

PubMed1995

Maze learning and morphology of frontal cortex in adult and aged basal forebrain-lesioned rats.

Maze performance and morphology of frontal cortex were assessed in young adult, middle-aged, and aged rats with and without lesions of the nucleus basalis magnocellularis. Although maze performance did not vary with age, neuron number and the thickness of superficial laminae were reduced in aged rats. Lamina II-III neurons were hypertrophied in middle-aged rats relative to both younger and older groups. At all ages, lesions significantly impaired maze performance. In young adult rats, lesions moderately reduced the size of lamina II-III neurons. This effect was more pronounced in middle-aged rats. Lesions in aged rats did not affect neuron size. The neuronal changes seen in middle-aged rats may reflect a compensatory response to the expression of other age-related neuronal changes, which may affect the ability of cortical neurons to respond to lesion-induced loss of cholinergic input.

Afferent Pathways↗

PubMed1994

Differential effects of dihydrotestosterone and estrogen on the development of motoneuron morphology in a sexually dimorphic rat spinal nucleus.

The rat lumbar spinal cord contains a sexually dimorphic motor nucleus, the spinal nucleus of the bulbocavernosus (SNB), whose motoneurons innervate perineal muscles involved in copulatory reflexes. Dendritic development of SNB motoneurons is biphasic and androgen dependent. During the first 4 postnatal weeks, SNB dendrites grow exuberantly, and subsequently retract to mature lengths by 7 weeks of age. After early postnatal castration, SNB dendrites fail to grow, and testosterone replacement restores this growth. In other systems, testosterone and its metabolites, dihydrotestosterone and estrogen, are important for somatic and neural sexual differentiation. The purpose of the present study was to examine the effects of castration and dihydrotestosterone or estrogen replacement on the growth of SNB motoneuron somata and dendritic arbors. Male rat pups were castrated on postnatal (P) day 7 and treated daily with either dihydrotestosterone propionate (DHTP; 2 mg) or estradiol benzoate (EB; 100 micrograms) until P28 or P49. By using cholera toxin horseradish peroxidase (BHRP) histochemistry, the soma size, dendritic length, dendritic extent, and arbor area of BHRP-labeled SNB motoneurons were measured and analyzed. Both DHTP and EB treatment supported the initial exuberant growth of SNB dendrites through P28, but EB treatment was ineffective in maintaining mature, adult lengths at P49. The possible sites of hormone action and functional implications of these hormonal treatments are discussed.

Animals↗

PubMed1994

A methodology for determining the patch-matrix compartmental location of extracellular single-unit recordings in the striatum of freely moving rats.

A methodology was developed to combine extracellular electrophysiological recording techniques in awake, behaving rats with immunohistochemical protocols to determine the placement of recording sites in the patch (striosome) or matrix (extrastriosome) regions of the striatum. The recording system includes a 3-barrel glass micropipette, which can be used to deposit Pontamine Sky Blue to mark a small number of neurons at the recording site. Subsequent immunostaining for calbindin allows the site to be localized within the patch-matrix organization. Other dyes or neuroanatomical probes can be ejected from other barrels of the recording pipette to label afferent and efferent structures. The methodology can be applied to many brain regions, providing for integrative studies of behavior and nervous system structure and function.

Animals↗