Effects of baclofen and phaclofen on receptive field properties of rat whisker barrel neurons.
Extracellular single-unit recordings were made in somatosensory cortical barrels of fentanyl-sedated rats. Whiskers were deflected singly or in paired combinations. Iontophoretically-applied (-)-baclofen disproportionately reduced weak responses, and phaclofen disproportionately increased them, resulting in more tightly focused or more broadly focused receptive fields, respectively. Both drugs had only minor effects on surround inhibition. In light of previous findings, we conclude that GABAA and GABAB mechanisms both act to enhance spatial contrast, but that the former plays a much greater role in enhancing temporal resolution.
Kyriazi
H T
HT
Department of Neurobiology, School of Medicine, University of Pittsburgh, PA 15261, USA.
Carvell
G E
GE
Brumberg
J C
JC
Simons
D J
DJ
D000818:Animals; D001418:Baclofen / Q000031:analogs & derivatives* / Q000494:pharmacology; D005110:Extracellular Space / Q000502:physiology; D005260:Female; D018755:GABA Agonists / Q000494:pharmacology*; D018756:GABA Antagonists / Q000494:pharmacology*; D007478:Iontophoresis; D008465:Mechanoreceptors / Q000187:drug effects / Q000502:physiology; D009475:Neurons, Afferent / Q000187:drug effects / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013003:Somatosensory Cortex / Q000187:drug effects / Q000502:physiology*; D014738:Vibrissae / Q000187:drug effects / Q000502:physiology*
D018755:GABA Agonists; D018756:GABA Antagonists; C052329:phaclofen; D001418:Baclofen