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Sex-specific brain deficits in auditory processing in an animal model of cocaine-related schizophrenic disorders.

Broderick PA, Rosenbaum T - Brain Sci (2013)

Bottom Line: The startle method operates through auditory pathways in brain via a network of sensorimotor gating processes within auditory cortex, cochlear nuclei, inferior and superior colliculi, pontine reticular nuclei, in addition to mesocorticolimbic brain reward and nigrostriatal motor circuitries.Key findings are: (a) Cocaine significantly reduced PPI in both sexes. (b) Females were significantly more sensitive than males; reduced PPI was greater in females than in males. (c) Physiological saline had no effect on startle in either sex.The data further suggest that hormones may play a role in these sex differences to acoustic startle reported herein.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology, Pharmacology & Neuroscience, The Sophie Davis School of Biomedical Education, The City College of New York, The City University of New York, New York, NY 10031, USA. broderick@med.cuny.edu.

ABSTRACT
Cocaine is a psychostimulant in the pharmacological class of drugs called Local Anesthetics. Interestingly, cocaine is the only drug in this class that has a chemical formula comprised of a tropane ring and is, moreover, addictive. The correlation between tropane and addiction is well-studied. Another well-studied correlation is that between psychosis induced by cocaine and that psychosis endogenously present in the schizophrenic patient. Indeed, both of these psychoses exhibit much the same behavioral as well as neurochemical properties across species. Therefore, in order to study the link between schizophrenia and cocaine addiction, we used a behavioral paradigm called Acoustic Startle. We used this acoustic startle paradigm in female versus male Sprague-Dawley animals to discriminate possible sex differences in responses to startle. The startle method operates through auditory pathways in brain via a network of sensorimotor gating processes within auditory cortex, cochlear nuclei, inferior and superior colliculi, pontine reticular nuclei, in addition to mesocorticolimbic brain reward and nigrostriatal motor circuitries. This paper is the first to report sex differences to acoustic stimuli in Sprague-Dawley animals (Rattus norvegicus) although such gender responses to acoustic startle have been reported in humans (Swerdlow et al. 1997 [1]). The startle method monitors pre-pulse inhibition (PPI) as a measure of the loss of sensorimotor gating in the brain's neuronal auditory network; auditory deficiencies can lead to sensory overload and subsequently cognitive dysfunction. Cocaine addicts and schizophrenic patients as well as cocaine treated animals are reported to exhibit symptoms of defective PPI (Geyer et al., 2001 [2]). Key findings are: (a) Cocaine significantly reduced PPI in both sexes. (b) Females were significantly more sensitive than males; reduced PPI was greater in females than in males. (c) Physiological saline had no effect on startle in either sex. Thus, the data elucidate gender-specificity to the startle response in animals. Finally, preliminary studies show the effect of cocaine on acoustic startle in tandem with effects on estrous cycle. The data further suggest that hormones may play a role in these sex differences to acoustic startle reported herein.

No MeSH data available.


Related in: MedlinePlus

(A) Depicts a longitudinal section of murine and/or human brain that shows the position of the pons in relation to cerebellum, midbrain and forebrain structures. (B) Depicts a microscopic cross section of the pons in the human brain that shows the position of the acoustic nerve.
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getmorefigures.php?uid=PMC4061862&req=5

brainsci-03-00504-f006: (A) Depicts a longitudinal section of murine and/or human brain that shows the position of the pons in relation to cerebellum, midbrain and forebrain structures. (B) Depicts a microscopic cross section of the pons in the human brain that shows the position of the acoustic nerve.

Mentions: The brain stem is of the utmost importance since lesion studies show that the inferior and superior colliculi, the pons and the caudal pontine reticular nucleus are critically important in the execution of the startle response. Lentner and Cohen studied the role of the inferior colliculus in the startle reflex as early as the late nineteen eighties [107]. All these neuronal networks, whether studied empirically or postulated theoretically, underlie the mechanism of action for acoustic startle and all must rely on the anatomic brain structure called the pons, seen below in Figure 6A,B.


Sex-specific brain deficits in auditory processing in an animal model of cocaine-related schizophrenic disorders.

Broderick PA, Rosenbaum T - Brain Sci (2013)

(A) Depicts a longitudinal section of murine and/or human brain that shows the position of the pons in relation to cerebellum, midbrain and forebrain structures. (B) Depicts a microscopic cross section of the pons in the human brain that shows the position of the acoustic nerve.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4061862&req=5

brainsci-03-00504-f006: (A) Depicts a longitudinal section of murine and/or human brain that shows the position of the pons in relation to cerebellum, midbrain and forebrain structures. (B) Depicts a microscopic cross section of the pons in the human brain that shows the position of the acoustic nerve.
Mentions: The brain stem is of the utmost importance since lesion studies show that the inferior and superior colliculi, the pons and the caudal pontine reticular nucleus are critically important in the execution of the startle response. Lentner and Cohen studied the role of the inferior colliculus in the startle reflex as early as the late nineteen eighties [107]. All these neuronal networks, whether studied empirically or postulated theoretically, underlie the mechanism of action for acoustic startle and all must rely on the anatomic brain structure called the pons, seen below in Figure 6A,B.

Bottom Line: The startle method operates through auditory pathways in brain via a network of sensorimotor gating processes within auditory cortex, cochlear nuclei, inferior and superior colliculi, pontine reticular nuclei, in addition to mesocorticolimbic brain reward and nigrostriatal motor circuitries.Key findings are: (a) Cocaine significantly reduced PPI in both sexes. (b) Females were significantly more sensitive than males; reduced PPI was greater in females than in males. (c) Physiological saline had no effect on startle in either sex.The data further suggest that hormones may play a role in these sex differences to acoustic startle reported herein.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology, Pharmacology & Neuroscience, The Sophie Davis School of Biomedical Education, The City College of New York, The City University of New York, New York, NY 10031, USA. broderick@med.cuny.edu.

ABSTRACT
Cocaine is a psychostimulant in the pharmacological class of drugs called Local Anesthetics. Interestingly, cocaine is the only drug in this class that has a chemical formula comprised of a tropane ring and is, moreover, addictive. The correlation between tropane and addiction is well-studied. Another well-studied correlation is that between psychosis induced by cocaine and that psychosis endogenously present in the schizophrenic patient. Indeed, both of these psychoses exhibit much the same behavioral as well as neurochemical properties across species. Therefore, in order to study the link between schizophrenia and cocaine addiction, we used a behavioral paradigm called Acoustic Startle. We used this acoustic startle paradigm in female versus male Sprague-Dawley animals to discriminate possible sex differences in responses to startle. The startle method operates through auditory pathways in brain via a network of sensorimotor gating processes within auditory cortex, cochlear nuclei, inferior and superior colliculi, pontine reticular nuclei, in addition to mesocorticolimbic brain reward and nigrostriatal motor circuitries. This paper is the first to report sex differences to acoustic stimuli in Sprague-Dawley animals (Rattus norvegicus) although such gender responses to acoustic startle have been reported in humans (Swerdlow et al. 1997 [1]). The startle method monitors pre-pulse inhibition (PPI) as a measure of the loss of sensorimotor gating in the brain's neuronal auditory network; auditory deficiencies can lead to sensory overload and subsequently cognitive dysfunction. Cocaine addicts and schizophrenic patients as well as cocaine treated animals are reported to exhibit symptoms of defective PPI (Geyer et al., 2001 [2]). Key findings are: (a) Cocaine significantly reduced PPI in both sexes. (b) Females were significantly more sensitive than males; reduced PPI was greater in females than in males. (c) Physiological saline had no effect on startle in either sex. Thus, the data elucidate gender-specificity to the startle response in animals. Finally, preliminary studies show the effect of cocaine on acoustic startle in tandem with effects on estrous cycle. The data further suggest that hormones may play a role in these sex differences to acoustic startle reported herein.

No MeSH data available.


Related in: MedlinePlus