Prenatal exposure to an NMDA receptor antagonist, MK-801 reduces density of parvalbumin-immunoreactive GABAergic neurons in the medial prefrontal cortex and enhances phencyclidine-induced hyperlocomotion but not behavioral sensitization to methamphetamine in postpubertal rats.
BACKGROUND
Neurodevelopmental deficits of parvalbumin-immunoreactive gamma-aminobutyric acid (GABA)ergic interneurons in prefrontal cortex have been reported in schizophrenia. Glutamate influences the proliferation of this type of interneuron by an N-methyl-D-aspartate (NMDA)-receptor-mediated mechanism. The present study hypothesized that prenatal blockade of NMDA receptors would disrupt GABAergic neurodevelopment, resulting in differences in effects on behavioral responses to a noncompetitive NMDA antagonist, phencyclidine (PCP), and a dopamine releaser, methamphetamine (METH).


METHODS
GABAergic neurons were immunohistochemically stained with parvalbumin antibody. Psychostimulant-induced hyperlocomotion was measured using an infrared sensor.


RESULTS
Prenatal exposure (E15-E18) to the NMDA receptor antagonist MK-801 reduced the density of parvalbumin-immunoreactive neurons in rat medial prefrontal cortex on postnatal day 63 (P63) and enhanced PCP-induced hyperlocomotion but not the acute effects of METH on P63 or the development of behavioral sensitization. Prenatal exposure to MK-801 reduced the number of parvalbumin-immunoreactive neurons even on postnatal day 35 (P35) and did not enhance PCP-induced hyperlocomotion, the acute effects of METH on P35, or the development of behavioral sensitization to METH.


CONCLUSIONS
These findings suggest that prenatal blockade of NMDA receptors disrupts GABAergic neurodevelopment in medial prefrontal cortex, and that this disruption of GABAergic development may be related to the enhancement of the locomotion-inducing effect of PCP in postpubertal but not juvenile offspring. GABAergic deficit is unrelated to the effects of METH. This GABAergic neurodevelopmental disruption and the enhanced PCP-induced hyperlocomotion in adult offspring prenatally exposed to MK-801 may prove useful as a new model of the neurodevelopmental process of pathogenesis of treatment-resistant schizophrenia via an NMDA-receptor-mediated hypoglutamatergic mechanism.
Abekawa
Tomohiro
T
Department of Psychiatry, Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, 060-8638, Sapporo, Japan. tabekawa@med.hokudai.ac.jp
Ito
Koki
K
Nakagawa
Shin
S
Koyama
Tsukasa
T
D000367:Age Factors; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D000697:Central Nervous System Stimulants / Q000494:pharmacology; D004195:Disease Models, Animal; D016291:Dizocilpine Maleate / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology*; D005260:Female; D008297:Male; D008694:Methamphetamine / Q000494:pharmacology; D009043:Motor Activity / Q000187:drug effects*; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D010320:Parvalbumins / Q000378:metabolism; D010622:Phencyclidine / Q000008:administration & dosage / Q000494:pharmacology; D017397:Prefrontal Cortex / Q000187:drug effects / Q000378:metabolism; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors* / Q000502:physiology; D012559:Schizophrenia / Q000503:physiopathology; D005680:gamma-Aminobutyric Acid / Q000187:drug effects / Q000378:metabolism
D000697:Central Nervous System Stimulants; D018691:Excitatory Amino Acid Antagonists; D010320:Parvalbumins; D016194:Receptors, N-Methyl-D-Aspartate; D008694:Methamphetamine; D005680:gamma-Aminobutyric Acid; D016291:Dizocilpine Maleate; D010622:Phencyclidine