The Experts below are selected from a list of 234 Experts worldwide ranked by ideXlab platform

Joseph C Glorioso - One of the best experts on this subject based on the ideXlab platform.

  • gene therapy for bladder overactivity and nociception with herpes simplex virus vectors expressing Preproenkephalin
    Human Gene Therapy, 2008
    Co-Authors: Hitoshi Yokoyama, Katsumi Sasaki, Michael E Franks, William F Goins, James R Goss, William C De Groat, Joseph C Glorioso, Michael B Chancellor, Naoki Yoshimura
    Abstract:

    Interstitial cystitis/painful bladder syndrome (IC/PBS) is a major challenge to treat. We studied the effect of targeted and localized expression of enkephalin in afferent nerves that innervate the bladder by gene transfer using replication-defective herpes simplex virus (HSV) vectors in a rat model of bladder hyperactivity and pain. Replication-deficient HSV vectors encoding Preproenkephalin, which is a precursor for Met- and Leu-enkephalin, or control vector encoding the lacZ reporter gene, were injected into the bladder wall of female rats. After viral vector injection, quantitative polymerase chain reaction showed high Preproenkephalin transgene levels in bladder and dorsal root ganglia innervating the bladder in enkephalin vector-treated animals. Functionally, enkephalin vector-treated animals showed reductions in bladder hyperactivity and nociceptive behavior induced by intravesical application of capsaicin; however, vector-mediated expression of enkephalin did not alter normal voiding. This antinociceptive effect of enkephalin gene therapy was antagonized by naloxone hydrochloride administration. Together, our results with HSV vectors encoding Preproenkephalin demonstrated physiological improvement in visceral pain induced by bladder irritation. Thus, gene therapy may represent a potentially useful treatment modality for bladder hypersensitive disorders such as IC/PBS.

  • antihyperalgesic effects of infection with a Preproenkephalin encoding herpes virus
    Proceedings of the National Academy of Sciences of the United States of America, 1999
    Co-Authors: Steven P Wilson, William F Goins, Mary Ann Bender, David C Yeomans, Ying Lu, Joseph C Glorioso
    Abstract:

    To test the utility of gene therapeutic approaches for the treatment of pain, a recombinant herpes simplex virus, type 1, has been engineered to contain the cDNA for an opioid peptide precursor, human Preproenkephalin, under control of the human cytomegalovirus promoter. This virus and a similar recombinant containing the Escherichia coli lacZ gene were applied to the abraded skin of the dorsal hindpaw of mice. After infection, the presence of β-galactosidase in neuronal cell bodies of the relevant spinal ganglia (lacZ-containing virus) and of human proenkephalin (Preproenkephalin-encoding virus) in the central terminals of these neurons indicated appropriate gene delivery and expression. Baseline foot withdrawal responses to noxious radiant heat mediated by Aδ and C fibers were similar in animals infected with proenkephalin-encoding and β-galactosidase-encoding viruses. Sensitization of the foot withdrawal response after application of capsaicin (C fibers) or dimethyl sulfoxide (Aδ fibers) observed in control animals was reduced or eliminated in animals infected with the proenkephalin-encoding virus for at least 7 weeks postinfection. Hence, Preproenkephalin cDNA delivery selectively blocked hyperalgesia without disrupting baseline sensory neurotransmission. This blockade of sensitization was reversed by administration of the opioid antagonist naloxone, apparently acting in the spinal cord. The results demonstrate that the function of sensory neurons can be selectively altered by viral delivery of a transgene. Because hyperalgesic mechanisms may be important in establishing and maintaining neuropathic and other chronic pain states, this approach may be useful for treatment of chronic pain and hyperalgesia in humans.

  • antihyperalgesic effects of infection with a Preproenkephalin encoding herpes virus
    Proceedings of the National Academy of Sciences of the United States of America, 1999
    Co-Authors: Steven P Wilson, William F Goins, Mary Ann Bender, David C Yeomans, Joseph C Glorioso
    Abstract:

    To test the utility of gene therapeutic approaches for the treatment of pain, a recombinant herpes simplex virus, type 1, has been engineered to contain the cDNA for an opioid peptide precursor, human Preproenkephalin, under control of the human cytomegalovirus promoter. This virus and a similar recombinant containing the Escherichia coli lacZ gene were applied to the abraded skin of the dorsal hindpaw of mice. After infection, the presence of β-galactosidase in neuronal cell bodies of the relevant spinal ganglia (lacZ-containing virus) and of human proenkephalin (Preproenkephalin-encoding virus) in the central terminals of these neurons indicated appropriate gene delivery and expression. Baseline foot withdrawal responses to noxious radiant heat mediated by Aδ and C fibers were similar in animals infected with proenkephalin-encoding and β-galactosidase-encoding viruses. Sensitization of the foot withdrawal response after application of capsaicin (C fibers) or dimethyl sulfoxide (Aδ fibers) observed in control animals was reduced or eliminated in animals infected with the proenkephalin-encoding virus for at least 7 weeks postinfection. Hence, Preproenkephalin cDNA delivery selectively blocked hyperalgesia without disrupting baseline sensory neurotransmission. This blockade of sensitization was reversed by administration of the opioid antagonist naloxone, apparently acting in the spinal cord. The results demonstrate that the function of sensory neurons can be selectively altered by viral delivery of a transgene. Because hyperalgesic mechanisms may be important in establishing and maintaining neuropathic and other chronic pain states, this approach may be useful for treatment of chronic pain and hyperalgesia in humans.

  • herpes virus mediated Preproenkephalin gene transfer to the amygdala is antinociceptive
    Brain Research, 1998
    Co-Authors: Wen Kang, Joseph C Glorioso, Marlene A Wilson, Mary Ann Bender, Steven P Wilson
    Abstract:

    To evaluate the role of the amygdala in pain modulation and opioid-mediated antinociception, a recombinant, replication-defective herpes virus carrying the human Preproenkephalin cDNA was injected bilaterally into the rat amygdala. Four days after gene delivery nociceptive behavior was assessed by the formalin test. Rats infected with the virus expressing Preproenkephalin showed a selective, naloxone-reversible abolition of phase 2 flinching behavior compared to rats infected with a control virus. The results implicate the amygdala in the control of pain and in opioid analgesia and demonstrate the use of recombinant herpes viruses as tools for studying gene function in specific neural pathways of the central nervous system.

George R. Uhl - One of the best experts on this subject based on the ideXlab platform.

  • subarachnoid morphine reduces stimulation induced but not basal expression of Preproenkephalin in rat spinal cord
    Anesthesiology, 1994
    Co-Authors: Gregory Crosby, John J A Marota, Takahisa Goto, George R. Uhl
    Abstract:

    BACKGROUND To evaluate directly the possibility that the potent exogenous opioid analgesic morphine may alter neuronal expression of opioid peptide genes, we assessed the effect of subarachnoid morphine on basal and noxious stimulation-induced expression of Preproenkephalin in spinal cord neurons. METHODS Twenty male Sprague-Dawley rats were prepared 48 h in advance with lumbar subarachnoid catheters. In the first phase, basal expression was evaluated in rats that received morphine 10 micrograms or saline intrathecally (n = 5 per group). Subsequently, the experiment was repeated (n = 5 per group), except that 10 min after morphine or saline administration rats received a hindpaw footpad injection of 50 microliters 5% formalin. Rats were killed during pentobarbital anesthesia 2 h later, and messenger RNA transcribed from Preproenkephalin was measured in lumbar spinal cord with quantitative in situ hybridization with a complementary sulfur 35-labeled oligonucleotide probe and emulsion autoradiography. RESULTS In control (nonstimulated) rats, 20% of the neurons in laminae I-II and 10% of those in laminae III-IV expressed Preproenkephalin. Injection of formalin increased the fraction of positive neurons by 34% (P < 0.05) and 20% (P < 0.05) in laminae I-II and V-VI, respectively, but had no effect on expression in laminae III-IV. Subarachnoid morphine did not alter basal expression of Preproenkephalin but markedly attenuated the noxious stimulation-induced increase in laminae I-II (P < 0.01) and V-VI (P < 0.05) by preventing the stimulation-evoked recruitment of Preproenkephalin-expressing neurons that otherwise would have occurred. CONCLUSIONS Subarachnoid morphine does not acutely alter basal expression of Preproenkephalin in spinal cord neurons but inhibits the increase in Preproenkephalin expression that would otherwise occur after noxious stimulation.

  • primary afferent stimulation acts through a 193 base pair promoter region to upregulate Preproenkephalin expression in dorsal horn of transgenic mice
    Molecular Brain Research, 1992
    Co-Authors: Motohide Takemura, David M Donovan, George R. Uhl
    Abstract:

    Abstract The expression of the principal opioid peptide gene, Preproenkephalin A, is exquisitely regulated by primary afferent inputs to the spinal and medullary dorsal horns. This regulated expression in response to neural synaptic activity has been referred to as trans-synaptic regulation. To define which DNA regions could mediate this trans-synaptic regulation, transgenic ‘HEC’ mice whose genomes include 193 bp of the human Preproenkephalin A promoter fused to a chloramphenicol acetyltransferase (CAT) reporter gene were studied. Mice received unilateral electrical stimulation of the trigeminal ganglion or adjuvant injection into the hindpaw, stimuli known to regulate dorsal horn proenkephalin expression in vivo. CAT activity conferred by this promoter displayed trans-synaptic upregulation with both stimuli. Although the level of the upregulation was 2- to 3-fold higher than the change in the wild type gene, several features of this induction paralleled aspects of the behavior of the wild-type gene: the rapidity of responses to trigeminal ganglion stimulation, the stimulation intensity dependence of responses to trigeminal ganglion stimulation and the time course of upregulation noted following adjuvant injection. Regulatory proteins binding to this restricted promoter region are thus likely to mediate aspects of dorsal horn enkephalin regulation by pain and other somatic stimuli.

  • Preproenkephalin promoter cassette confers brain expression and synaptic regulation in transgenic mice
    Proceedings of the National Academy of Sciences of the United States of America, 1992
    Co-Authors: David M Donovan, Motohide Takemura, Bruce F Ohara, Michael T Brannock, George R. Uhl
    Abstract:

    Abstract The Preproenkephalin A gene is a neurotransmitter gene whose expression can be modulated "trans-synaptically" by changes in neuronal activity. DNA sequences lying within 200 base pairs of this gene's transcription start site resemble consensus binding sites for several transcription factor families. In nonneuronal cell cultures, this promoter region is sufficient to mediate gene responses to depolarization, phorbol esters, adenylate cyclase, and calcium fluxes. To assess the role that these cis-acting elements could play in Preproenkephalin expression and regulation in vivo, the expression of a construct containing this 200-base-pair region fused to the chloramphenicol acetyltransferase gene was examined in transgenic mice. This promoter confers modest expression in brain, adrenal, and small intestine, with substantially higher levels in testis. These elements confer trans-synaptic regulation in two well-studied models of trans-synaptic Preproenkephalin upregulation but not in a third system, underscoring the specificity of the regulatory sequence elements implicated in the synaptic regulation of neuronal genes.

Jacqueline F. Mcginty - One of the best experts on this subject based on the ideXlab platform.

  • intrastriatal injection of the metabotropic glutamate receptor antagonist mcpg attenuates acute amphetamine stimulated neuropeptide mrna expression in rat striatum
    Neuroscience Letters, 1996
    Co-Authors: John Q. Wang, Jacqueline F. Mcginty
    Abstract:

    Abstract In chronically cannulated rats, microinjection of a competitive metabotropic glutamate receptor (mGluR) antagonist, (+)-α-methyl-4-carboxyphenylglycine (MCPG), into the dorsal striatum at doses of 0.4, 2 and 10 μg/1 μl did not affect basal levels of preprodynorphin, substance P and Preproenkephalin mRNAs in the dorsal striatum as revealed by quantitative in situ hybridization. However, intrastriatal MCPG (0.08, 0.4 and 2 μg/l μl) dose-dependently attenuated increases in the three mRNA expression induced by acute amphetamine injection (2 mg/kg, i.p.). MCPG had no significant effect on spontaneous, and amphetamine-stimulated, behavioral activities. These data indicate that activation of MCPG-sensitive mGluRs is necessary for upregulation of striatal neuropeptide mRNA expression in response to amphetamine exposure. However, the mGluR activity is not implicated in maintaining basal levels of the peptide gene expression in the striatum.

  • acute methamphetamine induced zif 268 preprodynorphin and Preproenkephalin mrna expression in rat striatum depends on activation of nmda and kainate ampa receptors
    Brain Research Bulletin, 1996
    Co-Authors: John Q. Wang, Jacqueline F. Mcginty
    Abstract:

    Abstract This study tested the role of N-methyl- d -aspartate and kainate/AMPA receptors in mediating mRNA expression of the immediate early gene zif/268 and the opioid peptide genes preprodynorphin and Preproenkephalin in rat forebrain following a single injection of methamphetamin. At 3 h after acute methamphetamine [4 mg/kg, intraperitoneally (IP)], quantitative in situ hybridization histochemistry revealed that zif/268 mRNA expression was increased in the dorsal striatum (caudoputamen) and in the sensory cortex. Preprodynorphin was increased in both dorsal and ventral striatum (nucleus accumbens) and Preproenkephalin was increased in the dorsal striatum. Pretreatment with (±)-3-(2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid (CPP) (10 mg/kg, IP), an N-methyl- d -aspartate receptor antagonist, blocked the methamphetamine-induced zif/268 mRNA expression in the striatum and in the region of sensory cortex representing the upper limb and nose. 6,7-Dinitro-quinoxaline-2,3-dione (DNQX) (100 mg/kg, IP), a kainate/AMPA receptor antagonist, did not reduce the ability of methamphetamine to induce zif/268 mRNA in striatal and cortical neurons. Furthermore, both antagonists caused a parallel blockade of methamphetamine-stimulated Preproenkephalin mRNA expression in the dorsal and ventral striatum but did not significantly affect methamphetamine-stimulated Preproenkephalin mRNA expression. CPP and DNQX reduced basal levels of zif/268 mRNA in cortical and striatal neurons but did not affect the constitutive expression of the two opioid mRNAs in the striatum. Neither antagonist had a significant effect on methamphetamine-induced demonstrate that both N-methyl- d -aspartate and kainate/AMPA receptor-mediated glutamatergic transmission is linked to modulation of the methamphetamine-stimulated opioid peptide gene expression in rat forebrain. Furthermore, N-methyl- d -aspartate receptors participate in methamphetamine-stimulated zif/268 expression.

  • cocaine binges differentially alter striatal preprodynorphin and zif 268 mrnas
    Molecular Brain Research, 1995
    Co-Authors: James B. Daunais, Jacqueline F. Mcginty
    Abstract:

    Abstract Several studies have demonstrated that cocaine increases preprodynorphin, c- fos , and zif /268 mRNAs in rat dorsal striatum. Multiple, closely spaced exposures to cocaine appear to elicit the greatest increases in dynorphin. However, the response of Preproenkephalin, c- fos and zif /268 mRNAs to such a dosing regimen is unknown. Therefore, we used a ‘binge’ paradigm to evaluate changes in mRNA for preprodynorphin, Preproenkephalin, c- fos and zif /268. Male Wistar rats received three hourly i.p. injections of saline or 10 or 20 mg/kg cocaine for 1, 5, or 10 days. Although cocaine-induced locomotor and stereotypical behaviors were significantly increased as compared to saline on days 1, 5 and 10, these behaviors were significantly less on day 10 than on days 1 and 5. One hour after the last injection on days 1, 5, or 10, the rats were anesthetized and decapitated for quantitative in situ hybridization histochemistry. C- fos mRNA was undetectable in all treatment groups whereas zif /268 mRNA in the dorsal striatum was increased in a dose-dependent manner (20 mg/kg > 10 mg/kg) but the intensity of hybridization signal decreased over time (1 day ⪢ 5 days > 10 days) as compared to that in saline-treated controls. In contrast, 10 mg/kg cocaine binges caused an increase in preprodynorphin, but not Preproenkephalin, mRNA in the dorsal, but not ventral, striatum in a time-dependent manner (day 10 ⪢ day 5 > day 1) whereas 20 mg/kg cocaine binges caused an increase in striatal preprodynorphin that was greater on day 1 and day 5 than on day 10. These data indicate that (1) c- fos , zif /268 and preprodynorphin mRNAs are differentially regulated in dorsal striatum, (2) behavioral tolerance results from chronic binges with 10 and 20 mg/kg cocaine and (3) the preprodynorphin genomic response exhibits tolerance to chronic high dose, but not low dose, cocaine binges.

Steven P Wilson - One of the best experts on this subject based on the ideXlab platform.

  • overexpression of proenkephalin in the amygdala potentiates the anxiolytic effects of benzodiazepines
    Neuropsychopharmacology, 2000
    Co-Authors: Wen Kang, Steven P Wilson, Marlene A Wilson
    Abstract:

    To elucidate the role of opioid peptides in control of the anxiety-like behavior and anxiety-reducing actions of benzodiazepines, a recombinant, replication-defective herpes virus (SHPE) carrying human Preproenkephalin cDNA was delivered to rat amygdala. Viral infection resulted in a strong, localized transgene expression after 2–4 days which diminished after one week. Anxiety-like behavior and the anxiolytic effect of diazepam were assessed three days after gene delivery using the elevated plus maze test. While SHPE infection alone did not reduce anxiety-like behavior, rats infected with SHPE exhibited a greater response to the anxiolytic effect of diazepam when compared to rats infected with a control virus (SHZ.1) containing the lacZ gene. The enhancement of diazepam action by SHPE was naloxone reversible, region-specific, and correlated with the time course of Preproenkephalin expression. The findings implicate amygdalar opioid peptides in regulating the anxiolytic effects of benzodiazepines. This study also demonstrates the usefulness of recombinant herpes virus in evaluating the role of single gene products within specific brain sites in pharmacological responses and complex behaviors.

  • antihyperalgesic effects of infection with a Preproenkephalin encoding herpes virus
    Proceedings of the National Academy of Sciences of the United States of America, 1999
    Co-Authors: Steven P Wilson, William F Goins, Mary Ann Bender, David C Yeomans, Joseph C Glorioso
    Abstract:

    To test the utility of gene therapeutic approaches for the treatment of pain, a recombinant herpes simplex virus, type 1, has been engineered to contain the cDNA for an opioid peptide precursor, human Preproenkephalin, under control of the human cytomegalovirus promoter. This virus and a similar recombinant containing the Escherichia coli lacZ gene were applied to the abraded skin of the dorsal hindpaw of mice. After infection, the presence of β-galactosidase in neuronal cell bodies of the relevant spinal ganglia (lacZ-containing virus) and of human proenkephalin (Preproenkephalin-encoding virus) in the central terminals of these neurons indicated appropriate gene delivery and expression. Baseline foot withdrawal responses to noxious radiant heat mediated by Aδ and C fibers were similar in animals infected with proenkephalin-encoding and β-galactosidase-encoding viruses. Sensitization of the foot withdrawal response after application of capsaicin (C fibers) or dimethyl sulfoxide (Aδ fibers) observed in control animals was reduced or eliminated in animals infected with the proenkephalin-encoding virus for at least 7 weeks postinfection. Hence, Preproenkephalin cDNA delivery selectively blocked hyperalgesia without disrupting baseline sensory neurotransmission. This blockade of sensitization was reversed by administration of the opioid antagonist naloxone, apparently acting in the spinal cord. The results demonstrate that the function of sensory neurons can be selectively altered by viral delivery of a transgene. Because hyperalgesic mechanisms may be important in establishing and maintaining neuropathic and other chronic pain states, this approach may be useful for treatment of chronic pain and hyperalgesia in humans.

  • antihyperalgesic effects of infection with a Preproenkephalin encoding herpes virus
    Proceedings of the National Academy of Sciences of the United States of America, 1999
    Co-Authors: Steven P Wilson, William F Goins, Mary Ann Bender, David C Yeomans, Ying Lu, Joseph C Glorioso
    Abstract:

    To test the utility of gene therapeutic approaches for the treatment of pain, a recombinant herpes simplex virus, type 1, has been engineered to contain the cDNA for an opioid peptide precursor, human Preproenkephalin, under control of the human cytomegalovirus promoter. This virus and a similar recombinant containing the Escherichia coli lacZ gene were applied to the abraded skin of the dorsal hindpaw of mice. After infection, the presence of β-galactosidase in neuronal cell bodies of the relevant spinal ganglia (lacZ-containing virus) and of human proenkephalin (Preproenkephalin-encoding virus) in the central terminals of these neurons indicated appropriate gene delivery and expression. Baseline foot withdrawal responses to noxious radiant heat mediated by Aδ and C fibers were similar in animals infected with proenkephalin-encoding and β-galactosidase-encoding viruses. Sensitization of the foot withdrawal response after application of capsaicin (C fibers) or dimethyl sulfoxide (Aδ fibers) observed in control animals was reduced or eliminated in animals infected with the proenkephalin-encoding virus for at least 7 weeks postinfection. Hence, Preproenkephalin cDNA delivery selectively blocked hyperalgesia without disrupting baseline sensory neurotransmission. This blockade of sensitization was reversed by administration of the opioid antagonist naloxone, apparently acting in the spinal cord. The results demonstrate that the function of sensory neurons can be selectively altered by viral delivery of a transgene. Because hyperalgesic mechanisms may be important in establishing and maintaining neuropathic and other chronic pain states, this approach may be useful for treatment of chronic pain and hyperalgesia in humans.

  • herpes virus mediated Preproenkephalin gene transfer to the amygdala is antinociceptive
    Brain Research, 1998
    Co-Authors: Wen Kang, Joseph C Glorioso, Marlene A Wilson, Mary Ann Bender, Steven P Wilson
    Abstract:

    To evaluate the role of the amygdala in pain modulation and opioid-mediated antinociception, a recombinant, replication-defective herpes virus carrying the human Preproenkephalin cDNA was injected bilaterally into the rat amygdala. Four days after gene delivery nociceptive behavior was assessed by the formalin test. Rats infected with the virus expressing Preproenkephalin showed a selective, naloxone-reversible abolition of phase 2 flinching behavior compared to rats infected with a control virus. The results implicate the amygdala in the control of pain and in opioid analgesia and demonstrate the use of recombinant herpes viruses as tools for studying gene function in specific neural pathways of the central nervous system.

Donald W. Pfaff - One of the best experts on this subject based on the ideXlab platform.

  • female Preproenkephalin knockout mice display altered emotional responses
    Proceedings of the National Academy of Sciences of the United States of America, 2001
    Co-Authors: A Ragnauth, A Schuller, Maria A Morgan, Johnny Chan, Sonoko Ogawa, J Pintar, Richard J Bodnar, Donald W. Pfaff
    Abstract:

    The endogenous opioid system has been implicated in sexual behavior, palatable intake, fear, and anxiety. The present study examined whether ovariectomized female transgenic Preproenkephalin-knockout (PPEKO) mice and their wild-type and heterozygous controls displayed alterations in fear and anxiety paradigms, sucrose intake, and lordotic behavior. To examine stability of responding, three squads of the genotypes were tested across seasons over a 20-month period. In a fear-conditioning paradigm, PPEKO mice significantly increased freezing to both fear and fear + shock stimuli relative to controls. In the open field, PPEKO mice spent significantly less time and traversed significantly less distance in the center of an open field than wild-type controls. Further, PPEKO mice spent significantly less time and tended to be less active on the light side of a dark–light chamber than controls, indicating that deletion of the enkephalin gene resulted in exaggerated responses to fear or anxiety-provoking environments. These selective deficits were observed consistently across testing squads spanning 20 months and different seasons. In contrast, PPEKO mice failed to differ from corresponding controls in sucrose, chow, or water intake across a range (0.0001–20%) of sucrose concentrations and failed to differ in either lordotic or female approach to male behaviors when primed with estradiol and progesterone, thereby arguing strongly for the selectivity of a fear and anxiety deficit which was not caused by generalized and nonspecific debilitation. These transgenic data strongly suggest that opioids, and particularly enkephalin gene products, are acting naturally to inhibit fear and anxiety.

  • Preproenkephalin promoter yields region specific and long term expression in adult brain after direct in vivo gene transfer via a defective herpes simplex viral vector
    Proceedings of the National Academy of Sciences of the United States of America, 1994
    Co-Authors: Michael G Kaplitt, A D Kwong, Steven P Kleopoulos, Charles V Mobbs, Samuel D Rabkin, Donald W. Pfaff
    Abstract:

    Abstract We have previously used a defective herpes simplex virus vector to express a foreign gene in the adult rat brain. One application of this technology would be the in vivo analysis of promoter function in brain after de novo transfer, which would allow the rapid generation of vectors with localized application in a broad range of mammalian species while avoiding influences of other nearby promoters. A 2.7-kb fragment of the rat Preproenkephalin promoter was placed upstream of the bacterial lacZ gene in our herpes simplex virus amplicon. A restricted pattern of lacZ expression was observed in vivo, which follows previously observed patterns of endogenous Preproenkephalin expression. These results, from the direct gene transfer into an adult animal brain for in vivo promoter analysis, demonstrate that sequence information that influences restricted expression of Preproenkephalin is located within 2.7 kb upstream of transcriptional initiation. lacZ expression was also observed in rat brain for 2 months after direct transfer, and PCR analysis confirmed the continued presence of amplicon DNA in lacZ-positive sections. Restricted and long-term expression observed with an endogenous promoter has important implications for gene therapy using viral vectors.