Hi Man Jiang, I am not totally sure of the functions but I find some clues. Spermine can block Kir channel (see http://jgp.rupress.org/content/120/1/53), while phosphocreatine can be metabolized by the neuron and serves a potential source of ATP which might be diluted into internal solution.

Dear Man Jiang,

I try to help for both points: (1) spermine and (2) creatine phosphate

1.

We introduced using of spermine (SP) for glial cell research, suggesting that SP should be included in the intracellular solution (ICS) for glial cell patch clamp (Kucheryavykh et al. 2008, GLIA, 56: 775-790) because (i) glial cells, but not neurons(!) preferentially accumulate polyamines, spermine, spermidine (Laube and Veh, 1997, GLIA,  19: 171-179; Biedermann et al, 1998, GLIA, 23: 209-220; Skatchkov et al., 2000, GLIA, Laube et al., 2002, J. Comp. Neurol., 444: 369-386) in large content up to mM range and (ii) SP is used for many functional goals in glial cells.

For example: a communication between astrocytes, the glial cells (Benedikt et al., 2012) in glial syncitium is impossible without SP, because gap-junction communications between astrocytes disappeared rapidly. Therefore, we rescued these communication with endogenous SP added in the patch pipette (or in ECS up to 1 mM).

Next example is:  we showed that without SP acidity of the cytoplasm can close Cx43 gap-junctions immediately, while SP keeps GJs open (Skatchkov et al., in press).

So, in summary:

(*) to keep functional state of inwardly rectifying K-channels (Kir4.1 channels) in glia and for the sake of (**) GJs communication and (***) a nativity of glial cytoplasm, we suggested 800 uM in ICS in patch pipettes (Kucheryavykh et al., 2008; Benedikt et al., 2012; Skatchkov et al., 2015, in press). For neurons it is not necessary.

2.

Phosphocreatine (or creatine phosphate) is a donor or energy and indeed is necessary for rapid energy use in case of anaerobic conditions. Also, it is used to convert ADP to ATP without of oxygen consumption, thus for production of ATP. On the other hand, because all investigators usually use ATP and GTP to add to their ICSs , creatine phosphate is added to ICS for a reason of (1) more rapid diffusion far away from patch pipette tip than large ATP can diffuse, and (2) as a rapid energy source, I assume.

Thanks, very cordially, Serguei.

Man- Neurons contain cytoplasmic polyamines (spermine is a polyamine) which block a plethora of ion channels, including the pore of the calcium permeable AMPA-receptors. These cells also contain an intact machinery (including the substrate to replenish APT, the energy source). When you make a whole cell patch clamp with an internal solution, you wash out  both of these compounds (in addition to many more). Adding these compounds to the internal solution compensates for the washout of the native compounds.

Internals with creatine phosphate are used in experiments where cells are held for longer recording periods- like examining long term synaptic plasticity, where the energy source is important for the long-term health of the cell after patching.

Internals with spermine are used when the biophysical properties of channels/receptors are to be evaluated- like in the case of calcium permeable AMPA receptors or inwardly rectifying potassium channels. These receptors are inwardly rectifying, and the rectifying properties are caused by the block of the channel by intra-cellular polyamines in a voltage dependent manner, and the lack of these polyamines/spermine in the cell leads a lack of rectification, and hence a change in the excitability of the cells.

hope this helps

Somehow I disagree with Jai, but in a good way. 

If anyone keeps in mind that glia (astrocytes, Bergmann and Mueller glia) versus neurons have different polyamine content (Laube and Veh, 1997; Biedermann et al., 1998; Skatchkov et al., 2000), then the question is "What we are speaking about?" We have extensive study on spermine (polyamines in common) in brain and we did not find much spermine immunoreactivity in neurons, specifically in adult brain. Juvenal brain contain polyamines in all cell types, but in contrast, we have robust staining in glial cells in adult brain, not in neurons. With the age polyamine content declines. Free polyamine spermine concentration in glia may be very high, up to 1 mM (Kucheryavykh et al., 2008). That is why we suggested to keep spermine concentration in patch pipettes for recording from the astrocytes (and Mueller, Bergmann glia as well). This is important for LTP registration because function of neurons are totally dependent on glial cell status. In addition when we saw that molecular propagation in astrocytic syncitium failed without spermine (Benedikt et al., 2012) we recommended to use spermine certainly keeping in mind that spermine opens astrocyte-to-astrocyte gap junctions (Benedikt et al., 2012) and removes hydrogen block from Cx43 (Skatchkov et al., 2015), the connexin widely expressed in glia and absent in neurons. We also warned that if brain slices are incubated after brain cut and slicing in polyamine free ACSF, the polyamine content is declined and the slices are not more physiological and often do not show LTP. So, we concluded, spermine and spermidine (the ultimate polyamines not like agmatine, putrescine) are very vital for brain function via glial face of the life. Finally, we can refer and appeal to wide literature on aging and polyamines, on diseases and syndromes, disorders and polyamines. I would love to discuss the matter with anyone.

Very cordially, Serguei.

Dear Man and Jei

it is important which age of neurons has been used: in young (9-15 days old) versus "adult" (after 22 days) in terms of neuron and astrocyte maturation. Particularly in rodents, guinea pig and rabbits after 21 days, the potassium inwardly rectifying channels (Kir4.1) are developed (while others declined (Schopf et al., 2004)) and Kir4.1 requires spermine to be rectified (Oliver et al., 1998; Skatchkov et al., 2000).

In neurons rectification of Kir2.x channels are basically provided by magnesium because the synthesis of spermine is stopped in neurons at adult neurons (Krauss et al., 2006; 2006). The only remnant spermidine synthesis was found in some synaptic terminals (Krauss et al., 2006; 2007) where it is probably important to keep AMPAR  rectified.

Also, spermine is necessary to keep glial Cx43-gap junctions open (Skatchkov et al., 2015) that is very important for astrocyte-to-astrocyte communication (Bendikt et al., 2012) otherwise function of glial syncitium will be failed.

So, if working on adult neurons you may ignore spermine or add about 0.1 mM, but not when patching glial cells that you need to use 1 mM (Kucheryavykh et al., 2008, Benedikt et al., 2012).

Cordially, Serguei.

To Serguei: Thanks very much for your detailed answer. I am convinced that spermine is necessary for  glia studies. 

To Jai: Thanks a lot!

I also thank Jiahao for his answer

In summary, spermine is a must for glia function and also studies about related channel properties; phosphocreatine is an energy supply together with ATP.   

Best,

Man

Please, remember that active concentration of spermine or spermidine is much lower than counted by addition to solutions because ATP and all phosphates as well as acid proteins lipids, etc. bind polyamines (Watanabe et al., 1991). In our paper Kucheryavykh et al. (2008) we used Kir channel behavior while titrating spermine in the patch pipette and using mathematical model. Also, please check Rozov and Burnashev (1999; Nature) who used similar calculations, but for neurons; this is to keep interneuron cytoplasm under control for free spermine activity about 18 micromoles. Neurons and glia are different in content of spermine and spermidine.

Very cordially, Serguei.