Amphetamine promotes recovery from sensory-motor integration deficit after thrombotic infarction of the primary somatosensory rat cortex.
The present studies were undertaken to examine 1) whether d-amphetamine sulfate administered to rats well after thrombotic infarction of the vibrissal cortical barrel-field within the primary somatosensory cortex affected the rate and completeness of behavioral recovery and 2) whether a dose-response relation exists between d-amphetamine sulfate dose and recovery of function. In a learning task requiring sensory-motor integration, 41 rats were trained to perform a motor response in a T-maze consequent to the detection of a vibrissal deflection cue. Once training was complete, unilateral (n = 29) or sham (n = 12) infarction was produced by a noninvasive photochemical technique. After infarction, T-maze performance was assessed repeatedly in rats receiving 2 (n = 10) or 4 (n = 10) mg/kg d-amphetamine sulfate or saline (n = 9) 24 hours prior to testing on days 4, 6, 9, and 11. The sham-operated control rats received d-amphetamine sulfate (n = 7) or no injections (n = 5). All three infarcted groups displayed a reliable and sustained behavioral deficit in performance that was not present in the sham-operated control animals. Although the performance of each infarcted group improved over the testing sessions after the first injection, the amphetamine-treated groups improved at a faster rate than the saline-injected group. The results further demonstrated a dose-response effect, with the 4 mg/kg amphetamine group recovering to within preinfarction levels 6-8 days earlier than the 2 mg/kg amphetamine and saline-injected groups. Moreover, both amphetamine-treated groups recovered more completely than the saline-injected group. Quantification of the chronic infarct area revealed no differences among the amphetamine-treated and saline-injected groups. These data provide further evidence of the facilitatory effect of d-amphetamine sulfate on recovery from brain injury and extend this effect to the enhancement of recovery subsequent to thrombotic infarction of the primary somatosensory cortex.
Hurwitz
B E
BE
Department of Psychology, University of Miami, Coral Gables, FL 33124.
Dietrich
W D
WD
McCabe
P M
PM
Alonso
O
O
Watson
B D
BD
Ginsberg
M D
MD
Schneiderman
N
N
D000661:Amphetamine / Q000494:pharmacology*; D000818:Animals; D002544:Cerebral Infarction / Q000150:complications* / Q000503:physiopathology; D007858:Learning / Q000187:drug effects* / Q000502:physiology; D008297:Male; D009043:Motor Activity / Q000187:drug effects* / Q000502:physiology; D009422:Nervous System Diseases / Q000188:drug therapy* / Q000209:etiology; D010812:Physical Stimulation; D011184:Postoperative Period; D051381:Rats; D011919:Rats, Inbred Strains; D012677:Sensation; D013003:Somatosensory Cortex / Q000503:physiopathology; D014738:Vibrissae / Q000502:physiology
D000661:Amphetamine