Pgk^nubian mutants display robust spontaneous action potential spiking in the dorsal longitudinal flight muscles at 38^oC, whereas wild-type flies display very little spontaneous activity. The onset of seizure activity in Pgk^nubian mutants is observed immediately when animals are shifted to 38^oC but rapidly subsides within minutes when maintained at 38^oC.

Pgk^nubian mutant second order neurons in the visual system lose the on/off-transients at 38^oC, suggesting a defect in synaptic transmission in the visual pathway. Pgk^nubian mutants require several minutes of exposure to 38^oC before the transients disappear. In addition, the recovery of on/off-transients on return to the permissive temperature in Pgk^nubian animals also show a slow recovery of photoreceptor repolarisation.

Pgk^nubian animals do not undergo instant paralysis but require several minutes of exposure to 38^oC before loss of motor activity. In addition, the recovery in Pgk^nubian animals is dependent on the length of exposure to 38^oC. After several minutes at 38^oC the Pgk^nubian mutants manifest a block of synaptic transmission, as evidenced by the loss of on-/off-transients in the visual system and the beahavioral paralysis.

The ADP/ATP ratio is found to be greatly elevated in Pgk^nubian mutants, with an approximately threefold decrease in ATP levels.

Pgk^nubian mutants show a dramatic reduction in lifespan, with a decrease in the T₅₀ (age at which 50% of the culture has died) by 75%, indicating a highly significant negative effect of reduced resting ATP levels on lifespan. In addition to reduced lifespan, Pgk^nubian animals are more sluggish than control animals at room temperature, even shortly after pupation before any change in viability is noted. Behavioural assays performed on 4- to 5-day old Pgk^nubian adults reveals a decrease in both climbing ability and spontaneous locomotion, consistent with a general reduction in locomotor activity secondary to altered ATP generation.

Pgk^nubian mutant larvae exhibit a >50% decrease in distance travelled and locomotor speed compared to wild-type larvae. These differences in motor output are accounted for by a decrease in the time spent in locomotion and a dramatic reduction in locomotor cycle frequency. In general, Pgk^nubian animals spend approximately 20% less time in locomotion, with a much higher propensity for pauses with head swinging/turning behavior, as manifested by an increase in direction changes in Pgk^nubian larvae.

Similar to controls, Pgk^nubian mutant larvae display approximately 54.6 varicosities per muscle fiber.

In general, average bouton diameter is larger at Pgk^nubian synapses compared to controls, especially in type 1B boutons and in branching boutons with two or more branch points.

Evoked synaptic transmission is not altered in Pgk^nubian mutants at 22^oC. The amplitudes of evoked excitatory junctional potentials (EJPs) and resting membrane potential are similar to controls. In addition, there is no change in paired pulse facilitation in Pgk^nubian mutants, indicating that short-term plasticity is intact. A slight reduction in spontaneous miniature EJP frequency from 1.4Hz in control animals to 1.1Hz in Pgk^nubian is observed, suggesting a smaller recycling pool of synaptic vesicles in the mutant. Motor pattern bursts are reduced by one-half in Pgk^nubian mutants, with only a mild reduction in burst duration compared to wild-type. Upon shifting to 36^oC, control animals show a two-fold increase in the frequency of motor pattern bursts. In contrast, the output of the central pattern generator is abolished completely in Pgk^nubian mutants at the elevated temperatures.

The resting membrane potential is lower in Pgk^nubian mutants than in controls at 36^oC, indicating that there is an immediate effect on membrane excitability that causes muscle membrane depolarisation compared with controls. Pgk^nubian mutants display a stimulation-dependent reduction in evoked EJPs compared with controls. During 10Hz nerve stimulation Pgk^nubian larvae show a gradual reduction in EJP amplitude, with a complete loss of synaptic transmission by 3 minutes on average. In contrast, without 10Hz nerve stimulation the amplitude of evoked responses in Pgk^nubian animals show little change. After the onset of 10Hz stimulation, however, Pgk^nubian synapses undergo a rapid reduction in response similar to animals that are stimulated shortly after the temperature is shifted to 36^oC.