Excitatory action of vasopressin in the brain of the rat: role of cAMP signaling.

Brain vasopressin plays a role in behavioral and cognitive functions and in pathological conditions. Relevant examples are pair bonding, social recognition, fear responses, stress disorders, anxiety and depression. At the neuronal level, vasopressin exerts its effects by binding to V1a receptors.

Oxytocin and vasopressin enhance synaptic transmission in the hypoglossal motor nucleus of young rats by acting on distinct receptor types.

Hypoglossal (XII) motoneurons innervate extrinsic and intrinsic muscles of the tongue and control behaviors such as suckling, swallowing, breathing or chewing. In young rats, XII motoneurons express V1a vasopressin and oxytocin receptors. Previous studies have shown that activation of these receptors induces direct powerful excitation in XII motoneurons.

Action of tachykinins in the hippocampus: facilitation of inhibitory drive to GABAergic interneurons.

By acting on neurokinin 1 (NK1) receptors, neuropeptides of the tachykinin family can powerfully excite rat hippocampal GABAergic interneurons located in the CA1 region and by this way indirectly inhibit CA1 pyramidal neurons. In addition to contact pyramidal neurons, however, GABAergic hippocampal interneurons can also innervate other interneurons. We thus asked whether activation of tachykinin-sensitive interneurons could indirectly inhibit other interneurons.

Pudendal motoneurons of the rat located in separated spinal nuclei possess nicotinic acetylcholine receptors having distinct pharmacological profiles.

Pudendal motoneurons are located in the ventral horn of the caudal lumbar spinal cord and innervate striated pelvic muscles implicated in sexual and eliminative functions. In rats they are distributed in the dorsomedial (DM) and dorsolateral (DL) nucleus. In male rats, dorsomedial motoneurons innervate the bulbocavernosus, the levator ani and the external anal sphincter, whereas dorsolateral motoneurons control the ischiocavernosus and external urethral sphincter.

Overview of cellular electrophysiological actions of vasopressin.

The nonapeptide vasopressin acts both as a hormone and as a neurotransmitter/neuromodulator. As a hormone, its target organs include kidney, blood vessels, liver, platelets and anterior pituitary. As a neurotransmitter/neuromodulator, vasopressin plays a role in autonomic functions, such as cardiovascular regulation and temperature regulation and is involved in complex behavioral and cognitive functions, such as sexual behavior, pair-bond formation and social recognition.