Involvement of adenosine in synaptic depression induced by a brief period of hypoxia in isolated spinal cord of neonatal rat.
The monosynaptic reflex (MSR), recorded extracellularly from the ventral root isolated, superfused spinal cords of neonatal rats (6-10 days post-partum), was rapidly depressed to 35-45% of control values by either cessation of superfusion (4 min stop-flow period) or by superfusion with anoxic medium (95% N2-5% CO2; 4 min). The depression was reversible, 85-115% recovery occurring after 15 min of restoration of flow or normoxic (95% O2-5% CO2) superfusion. 2-Chloroadenosine, a metabolically stable adenosine analogue, also reversibly inhibited the MSR, an effect which was antagonised by 10(-6) M 8-cyclopentyltheophylline (8-CPT). The depression of the MSR, caused by 4 min of hypoxia (either stop-flow or anoxic superfusion), was prevented by 10(-6) M 8-CPT. These results provide strong evidence for a critical involvement of adenosine in mediating early synaptic depression evoked by a brief period of hypoxia.
Lloyd
H G
HG
Department of Pharmacology, University of Sydney, N.S.W., Australia.
Spence
I
I
Johnston
G A
GA
D015762:2-Chloroadenosine; D000241:Adenosine / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn / Q000502:physiology*; D066298:In Vitro Techniques; D010100:Oxygen / Q000502:physiology*; D051381:Rats; D012023:Reflex, Monosynaptic / Q000187:drug effects*; D013116:Spinal Cord / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D013997:Time Factors
D015762:2-Chloroadenosine; D000241:Adenosine; D010100:Oxygen