Deprenyl blocks the aglycemia-induced depression of the synaptic transmission but not the ischemia-induced depression in neonatal rat spinal cord in vitro.
The protective action of R-(-)-deprenyl against the aglycemia (glucose-free) and the ischemia (glucose-free and O2-free)-induced changes in the synaptic transmission was investigated. The in vitro "glucose-free and O2-free" condition mimics in vivo ischemia where there is a deficiency of O2 and energy substrate, hence the term ischemia was used. The monosynaptic reflex (MSR) and polysynaptic reflex (PSR) potentials were elicited in the ventral root by stimulating the corresponding dorsal root in an isolated spinal cord from the neonatal rat. Aglycemia and ischemia depressed the spinal reflexes in a time-dependent manner and abolished them within 30 min. The 50% depression of the reflexes (T-50) occurred around 25 min for aglycemia and 15 min for ischemia. Creatine phosphate, an energy supplement, attenuated the aglycemia- and ischemia-induced depression of the reflexes. The T-50 values for both the reflexes were around 40 and 25 min for aglycemia and ischemia, respectively. Deprenyl (10 microM) blocked the aglycemia-induced depression completely but failed to block the ischemia-induced depression. The present results indicate that aglycemia and ischemia abolished the synaptic transmission simultaneously and energy supplementation partially attenuated the depression. The protective effects of deprenyl against aglycemia may not be due to its MAO-B action and suggest for the involvement of non-MAO-B mechanisms.
Jha
Archana
A
Department of Physiology, Institute of Medical Sciences, Banaras Hindu University, Varanasi 221005, India.
Das Gupta
Shyamal
S
Deshpande
Shripad B
SB
D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000818:Animals; D000831:Animals, Newborn; D015687:Cell Hypoxia / Q000187:drug effects / Q000502:physiology; D005260:Female; D005947:Glucose / Q000172:deficiency*; D066298:In Vitro Techniques; D008297:Male; D051381:Rats; D012642:Selegiline / Q000494:pharmacology*; D013116:Spinal Cord / Q000187:drug effects* / Q000378:metabolism; D009435:Synaptic Transmission / Q000187:drug effects* / Q000502:physiology
D012642:Selegiline; D005947:Glucose