Chandogya Upanishad: first mention of the Nadis

The oldest of the Upanishad texts originated from the 6th century B.C. – including the Chandogya Upanishads. This extract from chapter VIII.6 is perhaps the first mention of the Nadis.

Chhandogya-Upanishad

छान्दोग्यउपनिषद्

Chāndogya-Upaniṣad

Excerpts from Chap VIII.6

tadeṣa ślokaḥ ।"
śataṁ ca-ikā ca hr̥dayasya nāḍyas-tāsāṁ mūrdhānam-abhiniḥsr̥ta-ikā ।"
tay[ā]-{o}[u]dhrvam-āyann-amr̥tatvam-eti viṣvaṅṅ-anyā utkramaṇe bhavanty-utkramaṇe bhavanti ॥6॥

iti ṣaṣṭhaḥ khaṇḍaḥ ॥6॥