Possible Regulation of Intracranial Pressure by Human Atrial Natriuretic Peptide in Cerebrospinal Fluid

Abstract

To clarify the function of human atrial natriuretic peptide (hANP) in the cerebrospinal fluid (CSF), we examined hANP levels in the CSF of patients with various neurological diseases. The subjects were 16 controls without neurological disease and 45 patients with neurological disease. The 45 patients with neurological disease were divided into a group of 15 patients with intracranial hypertension (IH) and a group of 30 patients with normal pressure (NP). hANP in both CSF (1-hANP) and serum (s-hANP) was measured by RIA. Patients with IH were followed up. We analyzed correlations between 1-hANP and other parameters of CSF. Increase in concentration of 1-hANP was positively correlated with intracranial pressure (ICP; r = 0.72; p < 0.01), but not with other CSF parameters or with s-hANP. The concentration of 1-hANP appeared to be increased especially over a threshold value of ICP. In a follow-up study of patients with IH, changes in 1-hANP paralleled changes in ICP in every case (r = 0.79; p < 0.01). Our findings strongly suggest that 1-hANP plays an important role in the regulation of ICP in humans.

Multiplicity of cerebrospinal fluid functions: New challenges in health and disease

“…A prime neuropeptide candidate for acutely regulating CSFP is ANP. Collective experimental and clinical evidence demonstrates that: i) the CSF titer of ANP increases proportionally to CSFP elevation [98], ii) the CSF level of ANP is elevated in high-pressure hydrocephalus [99,100], iii) the ANP receptors in CP undergo a Vmax adjustment to compensate for the CSFP increase in hydrocephalus [88,101], and iv) the CPe is bioreactive to ANP [82] and modulates CSF formation [102] by a cGMP-dependent mechanism [86,103]. The putative regulation of CP-CSF by ANP and AVP occurs in acute high-pressure hydrocephalus but evidently not in chronic NPH [104].…”

“…Although beyond the scope of this review, the topic of deleterious anaerobic neuronal metabolism in hydrocephalus has been treated previously [136-138]. Concerning the second consideration, i.e., homeostatic mechanisms, the regulatory increases in ANP and AVP concentrations in CSF from elevated CSFP [98-100,104] evidently foster vascular perfusion of several regions. Even though up-regulated ANP may decrease CSF formation in ischemia and hydrocephalus, it does support CPe viability by increasing choroidal blood flow [139].…”

“…This trio of peptides down-regulates CSF formation via neuroendocrine effects on CPe [2,6,17,81-87]. ANP, AVP and FGF2 levels in the CP-CSF system are mainly under central control [6,98,203-208] and thus largely independent of plasma and peripheral effects. When the CNS is perturbed biochemically or physically, these peptidergic systems are activated to restore normal hydration and osmolality.…”

Cerebrospinal Fluid Secretion by the Choroid Plexus

“…Although a decrease in blood flow does not in itself reduce the rate of CSF production, the substrate availability from the vasculature can become rate-limiting. In addition, atrial natriuretic peptide (ANP) is released into the CSF when ICP is increased (355). ANP binds to the choroid plexus cell and inhibits CSF production by up to 35% (308).…”

Traumatic brain injury and recovery mechanisms: peptide modulation of periventricular neurogenic regions by the choroid plexus–CSF nexus

“…Atrial natriuretic peptide (ANP) concentration in human CSF increases in proportion to augmented ICP (Yamasaki et al . 1997). In an animal model, exogenous ANP presented intraventricularly curtails CSF formation (Steardo and Nathanson 1987) and reduces ICP.…”