[Neuron-neuroglia functional relation in the squid giant nerve fiber]. / Relaciones functionales neurona-neuroglia en la fibra nerviosa gigante del calamar.

The present work reviews the results of a series of physiological studies carried out in the giant nerve fiber of the tropical squid Sepioteuthis sepioidea, aimed at exploring the possible involvement of different second mediators and receptor systems, in the modulation of the long-lasting hyperpolarizing response of the Schwann cell membrane potential to axonal excitation. These studies provide experimental evidence on the existence of distinct receptors for ACh, octopamine, and a VIP-like endogenous peptide in the Schwann cell plasma membrane. They also indicate that the cyclic nucleotide adenosine 3',5' monophosphate may be playing a role as second messenger for the actions of the Schwann cell nicotinic cholinergic and the octopaminergic receptors, whereas the VIP receptor may be acting through the hydrolysis of polyphosphatidylinositols. These experimental findings are discussed as evidence for the existence of a complex multistep interaction between the giant axon and its satellite glial cells, the Schwann cell.

Relaciones functionales neurona-neuroglia en la fibra nerviosa gigante del calamar. / [Neuron-neuroglia functional relation in the squid giant nerve fiber]

The present work reviews the results of a series of physiological studies carried out in the giant nerve fiber of the tropical squid Sepioteuthis sepioidea, aimed at exploring the possible involvement of different second mediators and receptor systems, in the modulation of the long-lasting hyperpolarizing response of the Schwann cell membrane potential to axonal excitation. These studies provide experimental evidence on the existence of distinct receptors for ACh, octopamine, and a VIP-like endogenous peptide in the Schwann cell plasma membrane. They also indicate that the cyclic nucleotide adenosine 3,5 monophosphate may be playing a role as second messenger for the actions of the Schwann cell nicotinic cholinergic and the octopaminergic receptors, whereas the VIP receptor may be acting through the hydrolysis of polyphosphatidylinositols. These experimental findings are discussed as evidence for the existence of a complex multistep interaction between the giant axon and its satellite glial cells, the Schwann cell.

Modulation of the membrane potential of the Schwann cell of the squid giant nerve fiber.

1. The involvement of second messengers and of other chemical mediators, in the modulation of the membrane potential of the Schwann cell of the giant nerve fiber of the Tropical squid Sepioteuthis sepioidea is described. 2. The involvement of the cyclic nucleotide adenosine 3', 5' monophosphate (cAMP) in mediating the actions of the nicotinic Ach receptors of the Schwann cells is suggested. 3. The presence of octopaminergic receptors in the Schwann cells, mediating their actions through the activation of adenylate cyclase, is also described. 3. Receptors for vasoactive intestinal peptide (VIP) are also present on the Schwann cells, and their actions are mediated via a second messenger system that does not involve the activation of adenylate cyclase. 5. The three independent receptor systems referred above are able to interact in a complex way, which involves both their direct actions on the Schwann cell membrane potential and modulatory effects between the systems.